The logic of a controversy: The case of agent orange in Australia

Sm. Sci. Med. Vol. 29, No. 4, pp. 537-544, 1989 0277-9536/89 53.00 + 0.00 Printed in Great Britain. All rights reserved Copyright 0 1989 Maxwell Pergamon Macmillan plc

THE LOGIC OF A CONTROVERSY: THE CASE OF AGENT ORANGE IN AUSTRALIA

WAYNE HALL*

Division of Human Behaviour, School of Psychiatry, University of New South Wales, Kensington, N.S.W. 2033, Australia

Abstract-Since 1979 the Vietnam Veterans’ Association of Australia (VVAA) has claimed that exposure to the herbicide Agent Orange in Vietnam has adversely affected the health of Vietnam veterans and their families. A campaign for government recognition of diseases and disabilities caused by herbicide exposure led ‘in 1983 to the appointment of the Evatt Royal Commission which, after a 2-year inquiry, comprehensively rejected the WAA’s claim. The Evatt Commission’s findings have not been accepted by the VVAA and the claim continues to be defended, albeit in a highly qualified form. This controversy exemplifies the way in which a claim can attract public support, and persist despite rejections by Committees of Inquiry. An understanding of the reasons for the persistence of controversy requires an understanding of the logic of rejecting causal claims, the psychology of everyday inductive reasoning, and the interaction between politics and science.

Key words-controversy, Agent Orange, science, politics

THE AGENT ORANGE CLAIM

The herbicide Agent Orange was a 50: 50 mixture of the phenoxy herbicides 2,4-D and 2,4,5-T, the latter of which was contaminated with the toxic substance dioxin (TCDD). It was extensively used by American forces during the Vietnam War to destroy vegetation which provided cover to guerilla troops of the Viet Cong and North Vietnamese Army [I]. Since the late 197Os, the Vietnam Veterans’ Association of Australia (WAA) has claimed that exposure to Agent Orange has produced increased rates of birth defects among the children of Vietnam veterans, and of cancer and ‘toxic’ psychiatric syndromes among themselves [2]. This general claim presupposed a number of subsidiary claims, namely: that Australian Vietnam veterans were heavily exposed to this herbicide (and other chemicals) while serving in Vietnam; that (a) birth defects, (b) cancers and (c) psychiatric disorders have occurred at a higher than normal rate among Vietnam veterans and their families; and that any increases in the rates of (a), (b) and (c) are attributable to herbicide exposure.

The Agent Orange claim which was first made in the United States in 1978 was taken up in Australia in December 1979 when the Vietnam Veterans’ Asso- ciation of Australia (WAA) was founded to publi- cise the plight of Vietnam veterans and their families [3,4]. The VVAA subsequently conducted a media campaign which convinced many people that their claims were correct. There have not been any surveys of public opinion on the issue, but surveys of second year medical students at the University of New South Wales in 1987 and 1988 found that 58% and 62%, respectively, believed that the claims about birth

*Address for correspondence: National Drug & Alcohol Research Centre, PO Box 1, Kensington, N.S.W. 2033, Australia.

defects and cancer were ‘likely’ or ‘highly likely’ to be true. Fewer gave the same credence to the claim about psychiatric disorder (38% and 26%, respectively). Since medical students are likely to be better informed than the general community, it seems prob- able that there is widespread public support for most of the Vietnam veterans’ claims.

As a consequence of the public support that these claims attracted, the Fraser Liberal Government established the Vietnam Veterans’ Counselling Service and liberalised the conditions under which illnesses and disabilities among Vietnam veterans and their families would be treated by Veterans’ Affairs Hospitals. The Liberal Government also commis- sioned a series of epidemiological studies on the rates of birth defects and premature mortality among Vietnam veterans [5,6].

Despite these concessions the WAA continued to exert political pressure for an independent judicial inquiry into its claims. The Liberal Government resisted this pressure but the Labour Opposition and the Democrats succeeded in having a Senate Inquiry established in 1981 [I]. In 1983, the newly elected Hawke Labour Government honoured an election commitment by appointing a Royal Commission on ‘the Use and Effects of Chemical Agents on Australian Personnel in Vietnam’ with Mr Justice Phillip Evatt as Commissioner.

In 1985 the Evatt Commission produced a 9- volume report which comprehensively rejected the WAA’s claims [3]. As a result of the Evatt Com- mission’s findings, the amount of media coverage devoted to the issue declined but the claims continued to be made in a much weaker form [7]. A subsidiary controversy also developed about the adequacy of the Evatt Commission’s inquiry into the WAA’s claims [8-l 11.

The paper has two aims. First, it provides a succinct statement of the case against the VVAA’s

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claims. More detailed statements are available elsewhere 13, 12, 131. I will argue that Vietnam veterans have suffered as a consequence of their war service but their suffering is unconnected with exposure to Agent Orange. Second, having argued that the WAA’s claims about Agent Orange are insupport- able, I will discuss other reasons for their origin and persistence. I will argue: that the scientists who offer qualified support to the WAA’s claim make errors in the logic of causal inference; that the public perception of the controversy has been influenced by biases in the everyday interpretation of inductive evidence; and that the political history of Australian involvement in the Vietnam War influenced the way in which Vietnam veterans had to seek political support in an effort to win fair treatment for illnesses and disabilities connected with their war service.

THE CASE AGAINST THE AGENT ORANGE CLAIM

The Evatt Commission’s findings rebutted each of the three subsidiary parts of the WAA’s major claim (that Vietnam veterans had been exposed to Agent Orange, that rates of birth defects, cancer and psychiatric disorder had increased, and that any increases in the latter were attributable to herbicide exposure). First, on the issue of exposure, the Commission determined that the average Australian Vietnam veteran’s exposure to herbicides and insecticides was a small fraction of the exposure experienced by men who manufactured and sprayed the chemicals. Second, the Commission found that research on the rates of birth defects and premature deaths among Australian and American Vietnam veterans does not show any increase in the risk of adverse health outcomes which have been attributed to herbicide exposure in Vietnam. Third, the Commission concluded that the absence of any effects of exposure on Vietnam veterans and their families was consistent with our knowledge of the effects of the herbicides and other chemicals on persons who are occupationally exposed to them. The absence of any effects was also consistent with biological knowledge about the causes of birth defects, cancers and psychiatric disorder.

Exposure

The VVAA’s claim assumed that Australian Vietnam veterans were heavily exposed to herbicides and other environmental chemicals while serving in Vietnam. Both the Senate Standing Committee on Science and the Environment [1, Chap. 31 and the Evatt Commission [3, Vol. 1, Chap. 41 were satisfied by American records of the herbicide spraying pro- gramme and records from the Australian Task Force that the average level of direct and indirect exposure to herbicides of Australian troops who served in Vietnam was small.

The issue of exposure was much clearer with Australian than United States’ troops because Australian operations were largely confined to the Phoc Tuy Province [14] which was not heavily sprayed with Agent Orange [l]. The Evatt Com- mission’s conclusions on exposure were subsequently supported by an American study of the levels of TCDD in the body tissue of American veterans who

were more heavily exposed to the herbicide Agent Orange than Australian Vietnam veterans. Advocates of the herbicide claim had argued that bodily levels of TCDD would provide a reliable indication of herbicide exposure. Contrary to expectation, these veterans did not have higher bodily levels of TCDD than the normal population [15].

Birth defects

The case against the WAA’s claim is clearest in the case of birth defects. A large, well-conducted case-control study which had a 90% chance of detecting a doubling of risk showed that Australian Vietnam veterans were not at increased risk of fathering children with birth defects [5]. These findings were supported by two American studies [ 16, 171. The most convincing study was the Ranch Hand study [16] of the rates of birth defects among children fathered by men who sprayed the herbicides, and were thus heavily exposed to them. The second study was a case-control study by the Center for Disease Control which failed to find any increased risk of birth defects among men who had served in Vietnam [ 171.

The results of studies of birth defects in Vietnam veterans were supported by the results of several studies of birth defects among the children of men who manufactured the herbicides, and men who sprayed them. These men had higher average exposures than Australian Vietnam veterans, and they were exposed for a longer period, including the period when they fathered their children. If herbicide exposure has an effect on male reproductive performance, then these studies should have been able to detect it. Both studies failed to find any increased risk of birth defects or miscarriages [ 18, 191

The negative evidence of research studies is consistent with our knowledge of the mechanisms that cause birth defects. It is extremely unlikely that male exposure to chemicals would produce teratogenic birth defects in children born several years after exposure [20]. In order for male exposure to Agent Orange to produce teratogenic birth defects the toxic chemical (e.g. TCDD) would have to be stored for long periods (decades) in the male’s body, and there would have to be an improbable transfer of the toxic chemical to the foetus in utero at exactly the right time to interfere with normal foetal development [1, pp. so-911.

Although it is conceivable that chemical exposure could cause genetic mutations which were transmitted to a male’s offspring [ll], there are several reasons why it is extremely unlikely that genetic mutations have produced birth defects among the offspring of Vietnam veterans. First, the average level of exposure of Australian personnel was much lower than occupational exposures, and far below the estimated “no observed effect level” [3, Vol. 2, Chap. 5, pp. 29-351. Second, only one of the chemicals involved in the claim (TCDD) is suspected of being a weak mutagen [3, Vol. 4, Chap. 8, p. 2481. Third, extensive investigations of human populations exposed to known mutagens (e.g. irradiation at Hiroshima and Nagasaki) have failed to find evidence of genetically transmitted birth defects in two subse- quent generations [2 I].

The logic of a controversy 539

Cancers

The case against the cancer claim is not as strong as that against the claim on birth defects but it is still convincing. The most direct evidence comes from a large cohort study of Australian national servicemen which compared rates of mortality in the period since the end of their war service amongst those who did, and those who did not serve in Vietnam. This study did not find any increased risk of premature deaths due to cancer. It did find an increased risk of deaths due to other causes but these were unrelated to herbicide exposure, namely, accidental deaths, heart disease and alcohol-related disease [6], Similar results have been obtained from the Ranch Hand studies of mortality and cancer among the American personnel who sprayed the herbicides [3, Vol. 4, Chap. 81.

The effects of occupational exposure to herbicides on the risk of developing cancer are more controver- sial [22,23], a fact which has been emphasised by those who continue to support the WAA claim [9, lo]. Scandinavian researchers, for example, have reported increased risks of soft-tissue sarcoma and malignant lymphoma among railway workers who sprayed herbicides which included 2,4,5-T [24,25]. Other researchers have failed to replicate their results [3, Vol. 4, Chap. 81. Even if we accept the Scandina- vian evidence, however, there is no reason to expect an epidemic of these cancers among Australian Vietnam veterans. Their average exposure was a small fraction of that among the Scandinavian railway workers, the relative risk of developing the cancer was small, and the types of cancer which have been implicated are rare.

Psychiatric disorders

There is no direct evidence on rates of psychiatric disorders among Australian Vietnam veterans. Research on American Vietnam veterans suggests that there may be an increased rate of syndromes in which anxiety and depression are the major symptoms and which conform to the diagnostic category of post-traumatic stress disorder [1, Chap. 61.

There are good reasons for not attributing any increase in the rate of these’ disorders to chemical exposure in Vietnam [26]. First, the neuropsychiatric symptoms of chemical exposure (anxiety, depression and fatigue) are non-specific. Second, there are enormous differences between the average exposure to herbicides of Vietnam veterans and that of men with occupationally caused neuropsychiatric disorder; the former had at most an intermittent exposure to herbicides over a period of 1 or 2 years, while the latter have been exposed to toxic chemicals on a daily basis for 10 or more years. Third, there are also differences in the natural history of occupational neuropsychiatric disorders and those found among Vietnam veterans, namely, the former show symptoms of organic dementia which shows a downward course, whereas the latter suffer from fluctuating symptoms. Fourth, there is a more plausible explana- tion of the veterans’ psychiatric disorders, namely, that they are the usual psychiatric consequence of war service. This is supported by the fact that their disorders are clinically indistinguishable from the psychiatric disorders reported among veterans of the

First and Second World Wars, and the Korean and Arab-Israeli Wars.

Adverse eflects of Vietnam service

The evidence presented by the Evatt Commission suggests that Australian Vietnam veterans were adversely affected by their war service for reasons that were not connected with their exposure to herbicides in Vietnam. The Evatt Commission concluded that Vietnam veterans were at greater risk of psychiatric disorders and alcoholism, and of premature death due to accidents, alcohol-related diseases (e.g. cirrho- sis) and heart disease [3, Vol. 2, Chap. 6, Section 31. The Commission accordingly recommended that the provisions of legislation for war-service related disability and disease should be liberally interpreted in the case of Vietnam veterans.

WHY HAS THE AGENT ORANGE CLAIM PERSISTED?

An obvious reason for the failure of the Evatt Commission’s findings to resolve the controversy was a perceived inadequacy in its procedures and its findings. A number of different criticisms have been made of which only the most serious will be discussed here. Although none of these criticisms, I will argue, substantively affects the validity of the Evatt Com- mission’s findings they have substantially reduced their public credibility.

First, the WAA [A accused the Evatt Commission of bias in its evaluation of evidence. Although a variety of complaints have been made, most attention has focused on the Commission’s strong criticism of the research of Hardell and his colleagues, the fairness of which has been contested (22,231. As argued above, it is not necessary to enter the disagreement over the validity of the Swedish work for, even if we accept that the Commission was unfair to these investigators, its case against the WAA’s cancer claim has not been rebutted: Hardell and Axelsson’s findings have not been replicated by other researchers, and the exposure of Vietnam veterans was at most a small fraction of that experienced by the men in Hardell et al.‘s studies. This point, however, is inevitably lost in the media reporting. What remains is a public perception of controversy and disagreement between scientists which, for reasons to be discussed below, operates in the favour of the WAA.

Second, the Evatt Commission has been accused of plagiarising material from the submission of the Australian subsidiary of the Monsanto Chemical Company which was one of the manufacturers of the Agent Orange used in Vietnam [Gil]. It is undeni- able that material from the Monsanto submission was used in the Commission’s report. It is equally clear that it was unwise for the Evatt Commission to have done so since any evidence given by the chemical companies would be perceived as tainted by the general public [8]. But the Commission’s critics have not demonstrated that the Evatt Commission’s conclusions were wrong. The public has been encouraged to draw that conclusion by reasoning that the conclusions must be false since they were supported by Monsanto, and it was in Monsanto’s interests to deny the WAA’s claim. This form of cui bono reasoning

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has pervaded the controversy, creating a presumption in favour of the veterans’ claim. Given this fact, the Commission’s use of the Monsanto material ensured that the public would perceive its conclusions as inadequate.

Third, the government rejected the Commission’s finding that Agent Orange was ‘not guilty’. The Minister for Veterans’ Affairs, Senator Gietzelt, preferred a conclusion that “the case for a link between Agent Orange and health problems among Vietnam veterans has not been established” [27]. Other critics of the Evatt Commission have argued for a similar finding [8,9, 111.

I believe that the Commission’s conclusion is defensible but the reasons for saying so are difficult to communicate to the public. The alternative ‘not proven’ conclusion recommended by the government and the Commission’s critics is too weak. It assumes that there is a prima facie case in favour of the WAA’s claim when none was presented at the inquiry. The VVAA were unable to meet the Commission’s challenge to present its ‘10 best shots’: 10 veterans who combined evidence of exposure to Agent Orange with one or more of the conditions. which have been attributed to it [3, Vol. 2, Chap. 6, Section 31. The 10 cases that were presented by the WAA either provided doubtful evidence of herbicide exposure or they suffered from illnesses that had not been connected with herbicide exposure.

The ‘case’ that the WAA’s counsel argued before the Evatt Commission was that the WAA’s claim had to be accepted because it was impossible to reject it. Their counsel argued that the VVAA’s claim could not be ruled out because one could not exclude the possibility that a small group of unidentifiable Vietnam veterans were exposed to chemicals which may have caused adverse health effects at such a low level of incidence that they were undetected by any of the epidemiological studies that have been carried out to date. This is a logical possibility but an empirically empty one. Given the sort of assump- tions that have been made (e.g. that the rate of birth defects was doubled among the 5% of veterans who were allegedly heavily exposed) [28], any such increase in adverse health outcomes would be un- detectable even if all Australian Vietnam veterans were studied [21].

Fourth, the Evatt Commission’s findings also suffered by comparison with the out of court settlement of the United States Class Action brought by Vietnam veterans against the chemical companies which manufactured Agent Orange. The size of the $180,000,000 (U.S.) settlement has more than any other factor convinced the public of the justice of veterans’ claims about Agent Orange.

The Evatt Commission attempted to address this class action issue with a discussion of the reasons for the out of court settlement, namely, the real fears that both sides had of losing the action. The chemical companies’ lawyers were concerned about the financial losses that their clients would risk while litigation continued and the chances of an un- favourable jury decision given the public perception of the issue. The Vietnam veterans’ lawyers were concerned because of the difficulties they faced in establishing, first the causal claim on the balance of

probabilities, and then the liability of individual companies for individual veterans’ injuries. The problems of both the plaintiffs and defendants had been pointed out by Judge Weinstein in his Preliminary Memorandum [3, Vol. 6, Chap. 1 I]. As with so much of the detailed argument in the Evatt Commission report, the analysis of the non-epistemic reasons for the out of court settlement were lost in the media coverage.

The logic of causal inference

There are some scientific critics of the Evatt Com- mission who have defended the WAA’s modified claim [I 1,281. I will argue that these critics have refused to accept that there are circumstances in which it is reasonable to infer the absence of a causal connection between two events. They implicitly demand a demonstrative proof of the non-existence of a causal relationship, something which it is of course impossible to provide. Indeed, it is impossible to provide a demonstrative proof of anything in science, as Hume [29] showed over 200 years ago. Under certain circumstances, it is nonetheless reasonable to believe that, or what amounts to the same thing, to act as if, a causal relationship does not exist [30].

Evidence for the absence of a causal relationship between a putative cause (A) and a putative effect (B) requires two things. First, evidence of the absence of a relationship between (A) and (B). This should be provided by research studies which have an opportu- nity to detect such a relationship, if one exists. The latter requirement can be met by statistical power analysis which enables researchers to calculate the sample size required to detect a relationship of a given magnitude [31]. Second, there should be good reasons for doubting that a relationship exists. The strongest reason is an inconsistency between the existence of the relationship and other well-established biological knowledge [32]. For example, the absence of a conceivable mechanism whereby (A) could cause (B), in conjunction with evidence of the absence of any relationship between (A) and (B), constitutes good reasons for believing that there is no causal relationship between (A) and (B) [33].

Both of these conditions have been satisfied in the Evatt Commission’s findings. The Commission was able to reject the claims about birth defects and cancer because several attempts to discover such effects among veterans and their offspring had failed. In the case of birth defects and mortality, this included large studies with adequate statistical power to detect small increases in the overall rates of birth defects and premature mortality. In addition, there were strong reasons for not expecting increases (the lack of a mechanism in the case of birth defects, and a low level of exposure and rarity of the cancer in the case of premature deaths attributable to cancer). In the case of psychiatric disorder, any increase in rate was attributable to other aspects of war service since the type of disorders observed among veterans are indistinguishable from those observed among the veterans of previous wars [26].

Reversed onus of proof

The difficulties in refuting a causal claim were com- pounded by a reversed onus of proof that implicitly


operated throughout the controversy. This placed the obligation on the critics of the WAA’s claim to refute it, rather than on the WAA to provide aprima facie case for it. The WAA’s spokesmen did not present a strong case in favour of their claim but challenged those who rejected it to prove that the claim was false. This reversed onus of proof was not accepted by the Evatt Royal Commission [3, Vol. 1, Chap. 21.

There were at least two reasons for the reversed onus of proof. One was the carrying over into the public arena of the ‘benefit of the doubt’ provision contained in the legislation which governs claims made by war veterans against the Department of Veterans’ Affairs. Because war veterans do not have recourse to the usual legal remedies for injury (litigation for damages due to negligence), they have been given the benefit of the doubt in the evaluation of claims for free treatment or compensation, for illness and disability connected with their war service. That is, in cases where there is uncertainty about the connection between war service and ill health, the onus is on the Department to disprove a veteran’s claims rather than on the veteran to establish his claim [ 1, Chap. 91. The second reason for the reversed onus of proof has already been referred to: the public presumption of truth in favour of the veterans’ claims because of the economic interests that the govem- ment and chemical companies had in denying them.

Errors in everyday induction

Errors in reasoning about causal inference and a reversed onus of proof have affected many of the participants in the Agent Orange debate. Different processes have shaped the public perception of the Agent Orange controversy, insight into which can be gained from research on heuristics and biases in human reasoning [34,35]. This literature reveals several cognitive biases and heuristics that affect our ability to reason inductively. It is not difficult to see how they may have affected public perception of the evidence in favour of the WAA’s claims about Agent Orange.

Most of us are guilty at some time in our lives of drawing unjustified inferences about a population from sample information that is biased [35]. We seem to assume that samples are representative unless there is evidence to the contrary. Thus, well-public&d cases of birth defects, cancer and psychiatric disorder among the membership of the WAA have been interpreted [lo, 361 as compelling evidence for the WAA’s claim. It is implicitly assumed that the WAA membership is representative of all Vietnam veterans, thereby ignoring the possibility that ill veterans may be selectively recruited into the WAA. If Vietnam veterans who experienced health problems were more likely to join the VVAA, the rates of ill health among WAA members would exceed those in the general community of Vietnam veterans [21].

The impact of biased data is enhanced by the greater memorability of vivid individual instances of suffering and disease which feature in the media coverage of the issue [34]. Research on the public’s perception of the frequency of various causes of death, for example, indicates that people over- estimate the frequency of rare causes of death in

accordance with the amount of media attention they receive [37]. A small number of birth defects among the children of Vietnam veterans accordingly has much more psychological impact than a pallid statistical summary based upon the rates of birth defects in representative samples of veterans and controls. Hence, frequent repetitions of the WAA’s claim in the media, especially when illustrated by poignant instances of individual suffering, have created the false impression that Vietnam veterans and their families have been afBicted by an epidemic of birth defects, cancer and psychiatric disorder.

A second cognitive limitation is that human beings find it difficult to generate alternative explanations of relationships between events [35]. In the case of the Agent Orange controversy, an unconscious inference has been made that, if there has been an increase in the rate of any of these adverse health outcomes, this must have been because of chemical exposure in Vietnam. The fact that birth defects, cancers and psychiatric disorders occur in people who have not been exposed to herbicides is forgotten, as is the fact that all three events are relatively common in the community. Birth defects occur in between 2% and 4% of births [38,39]. Deaths due to cancer would be expected to have occurred in nearly 0.2% of men in the veterans’ age group [1, Chap. 7’J Disabling psychiatric disorders occur in as many as 3% of the community [40,41]. There is also a failure to appreci- ate that war service can produce adverse health effects for a variety of reasons that are unconnected with environmental chemicals, e.g. alcohol abuse, cigarette smoking, risk taking and, perhaps, stress.

Acceptance of the WAA’s claim about Agent Orange has been encouraged by the widespread acceptance of a false antithesis. For many people, the choice of sides in the Agent Orange controversy is a choice between what are perceived as two mutually exclusive positions: one either supports the veterans’ demand for justice and hence supports the WAA’s claim about Agent Orange, or one is against the claim, and hence against the veterans’ right to fair treatment. This interpretation is encouraged by the press coverage of the issue which confounds moral and factual issues [42,43]. This is abetted by joumal- ists’ attempts to provide a ‘balance’ by giving repre- sentatives of the ‘two’ sides more or less equal time WI.

We should not be surprised that the controversy is so widely understood in such terms. When the public is not in a position to judge the evidence for themselves they use dramatic representations to help them choose between the competing sides [45]. In simple terms, they try to decide who is the hero and who is the villain [46], with predictable results in a clash between suffering veterans and a seemingly hard- hearted government protecting the interests of the chemical companies. For all these reasons, it has proven difficult to convince people that Vietnam veterans’ have a right to fair treatment which does not depend upon their having been poisoned by Agent Orange.

Politics

So far I have suggested reasons why the WAA’s claims attracted public support and reasons why

542 WAYNE HALL

scientific critics have been reluctant to accept the findings of the Evatt Royal Commission. It is now appropriate to ask why the WAA took up the claim in the first place, and why its leadership persists in defending it.

The Agent Orange controversy grew out of Vietnam veterans’ grievances about the treatment they received from the Department of Veterans’ Affairs [4]. Some grievances were shared with the veterans of previous wars, namely, the Department’s mode of investigating veterans’ health complaints was perceived as a reflection on the veterans’ honesty and character. This was an understandable reaction since a senior medical member of the Depart- ment (Rose) is on public record as believing that Orange Agent claimants were malingerers [47J. Other grievances were unique to veterans of the Vietnam War, namely, a ‘generation gap’ between the younger Vietnam veterans and the Second World War veterans who held senior posts in the Department and in the Returned Services League which historically has championed the cause of war veterans. The differences in age and experience were heightened by the fact that many of the Second World War veterans seemed to believe that Vietnam veterans had not fought in a ‘real’ war [4],

Appeals to address these grievances which were directed to the then Liberal Party Government were unsuccessful [4]. The Menzies Liberal Government had committed Australian troops to Vietnam [ 141 but its successor seemed unreceptive to the veterans’ complaints. For historical reasons, there seemed to be little prospect of the Vietnam veterans requesting help from the Labor Opposition. The Labor Party had opposed Australian involvement in the Vietnam War and had campaigned for the withdrawal of Australian troops. In the late 1960s the Labor Party had supported public protests against Australian involvement in Vietnam, and on occasion there had been physical clashes between Labor supporters and Vietnam veterans. Vietnam veterans had resented the lack of support they had been received from the home front and many blamed the Labor Party for this. They especially resented trade union bans on the delivery of mail to them while in Vietnam [48].

The WAA was formed to better the treatment of Vietnam veterans when the first American claims were made about Agent Orange. These claims were widely publicised and received support from some scientific figures. The apparent validity of the claim, and the lack of response from the Fraser Liberal Government, made the Agent Orange theory very attractive. It gave the VVAA the political and public support it lacked because Vietnam veterans and members of the Labor Party found a common cause in their condemnation of the use of toxic chemicals during the Vietnam War. This is not to suggest that the VVAA embraced the claim for purely political reasons. The leadership of the WAA were sincere advocates of the Agent Orange theory because of their extensive personal experience with health problems among their membership [4].

In this historical context, the VVAA’s advocacy of the Agent Orange claim improved the lot of Vietnam veterans and their families. The public support it attracted forced the Liberal Government to repeal

discriminatory legislation and to introduce a Vietnam Veterans’ Counselling Service. Whatever its past successes, there are now less compelling reasons for the continued advocacy of the Agent Orange claim. By the WAA’s own admission, the Evatt Com- mission’s ‘&. . . recommendations that veterans be treated for ill health effects such having been caused by stress achieve the same result as a finding that they were chemically poisoned” [7, p. 301.

Despite the ground gained by the Agent Orange campaign and the practical consequences of the Evatt Commission’s findings on the effects of war service, the WAA continues to advocate the Agent Orange claim in a muted form. This is in large part because some of its leaders and members feel they were betrayed by the Evatt Royal Commission, and scientific criticisms of the latter’s findings seem to provide reasons for the veterans’ resentment. But even if there had been less criticism of the Evatt Commission’s findings it is unlikely that some veterans would have been convinced. In the case of the WAA members with whom I have talked, it is doubtful that any evidence would persuade them that their claim is unsustainable.

The prospects of resolution

Because of the complicated determinants of the Agent Orange controversy, it is difficult to make predictions about whether the controversy will be resolved, and if so, how this will be achieved. I will nonetheless hazard two predictions.

First, I predict that the controversy will be resolved, if at all, by ‘natural death closure’ [49]. It will not be resolved by the gradual emergence of consensus on the status of the claim. Rather, it will slowly fade from public view as the energy and motivation of the claimants is directed elsewhere. This outcome seems the most likely given the failure to achieve closure by epidemiological studies, a par- liamentary inquiry, government concessions, and the full judicial inquiry provided by the Evatt Royal Commission.

The reasons for the failure of resolution are clear with the advantage of hindsight. The Agent Orange controversy is too large and untidy, the skein of scientific, political and ethical issues too entangled, to permit a co-operative disentanglement that will sat- isfy the general public or Vietnam veterans. The arguments of proponents and opponents do not seem to make contact with each other. At times, the two sides seem to live in two worlds defined by very different ways of thinking about and ‘seeing’ the evidence, in much the same way as Hanson [50] has argued Tycho Brahe saw the sun ‘rise’ while Kepler ‘saw’ the earth rotate to bring the sun in view.

The VVAA argues from the compelling personal experience of suffering among its members and their families. It sees no need to make a scientific case for its claim; rather it challenges the government to rebut its claim beyond reasonable doubt. The govem- ment and the Judiciary are unimpressed by individual cases. They demand epidemiological evidence of an increased occurrence of birth defects, cancers and psychiatric disorder which can be shown, on the balance of probabilities, to have been caused by exposure to Agent Orange. The public’s perception


of the debate is coloured by a communal bad con- science about the treatment of its veterans. And there is no authority which is accepted as an impartial arbiter that can assist the emergence of a negotiated resolution.

My second prediction concerns the long term public view of the truth of the WAA’s claim. It is that as the controversy fades, it will leave as a legacy a widespread public conviction that the VVAA’s claims were true. The principal reason is that the public has accepted the VVAA’s argument that the onus of proof lies with the government to conclu- sively refute the VVAA’s claim. Since the government is perceived to have ‘failed’ in this task, the public’s uncertainty will be resolved by ‘giving the benefit of the doubt’ to the veterans’ claim.

CONCLUSION

The Evatt Commission provided a strong case against the claim that exposure to Agent Orange and other chemicals in Vietnam has caused birth defects, cancers and psychiatric disorders among Australian Vietnam veterans. The persistence of the claim in the face of the Evatt Commission’s rejection of it depends upon the superficial attraction of criticisms of the Evatt Commission’s findings; the refusal of scientific critics to accept evidence for the absence of a causal connection; the ubiquity of common errors in everyday inductive reasoning; the mistaken assumption that the veterans’ case for fair treatment depends upon their having been poisoned by chemicals in Vietnam; and the slow ebbing of the political tide which generated the controversy and sustained it for the past 9 years.

Acknowledgement.s-The views expressed in this paper are a modified version of views that I presented to both the Senate Standing Committee Inquiry and the Evatt Royal Commission. Although 1 accept sole responsibility for the views expressed here, I would like to thank the following people for their helpful comments on earlier versions of this paper: Ralph Anvas, Kevin Bird, Arthur L. Caplan, Allen Christophers, H. Tristram Engelhardt, George Humphrey, Allan Mazur. Donald MacPhee, Jim MacKenzie and Gordon Parker.

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The logic of a controversy: The case of agent orange in Australia

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