Chapter 10
Is a partial defence justified?

Arguments against a partial defence

10.35In assessing the arguments in favour of partial defences we have, necessarily, addressed many of the counter-arguments already, but there are four stand-alone arguments against partial defences that warrant mention.

Partial defences tend to be co-extensive with mandatory sentencing

10.36As highlighted throughout this part, with few exceptions, partial defences go hand in hand with mandatory sentencing for murder. Law reform bodies here and overseas have noted the mandatory penalty’s historical co-extensiveness with partial defences, and jurisdictions where mandatory sentencing has been abolished have, in the main, found that to point against partial defences.820 Two law reform bodies to have recommended against abolition of partial defences, the Law Commission of England and Wales and the Queensland Law Reform Commission, were working on the basis that the mandatory sentence for murder was not open for reform, and that was highly relevant to their recommendations.821

Partial defences are anomalousTop

10.37For other crimes, if the elements of an offence are proved, that is sufficient to convict, and differences in the seriousness of particular cases are addressed at sentencing. Culpable homicide is the only kind of crime where, despite proof of the elements of murder, a person may still be convicted of another less serious offence (manslaughter or, in relevant cases, infanticide) if a partial defence applies. These are cases where the defendant intentionally caused death but extenuating circumstances are seen to justify a description of culpability or sentencing consequences other than those that follow a murder conviction.822 Thus, the Law Commission of England and Wales has described the idea of a partial defence as “something of a misnomer”, better understood as “the way that the law has created space for discretion in sentencing in murder cases”.823 Despite this, some suggest a partial defence model could be applied beyond homicide,824 while others resist the idea partial defences are anomalous just because they are unique to the law of homicide.825

Partial defences are not well suited to taking account of mitigating circumstancesTop

10.38A compelling argument, which has considerable practical significance and was reviewed at length by this Commission in 2007,826 is that partial defences are a second-best way to take account of mitigating circumstances.
10.39One reason for this is that a wide range of circumstances may mitigate a defendant’s culpability, and unless it is suggested there should be a partial defence for every such circumstance, there will inevitably be arbitrariness in which mitigating factors are singled out for recognition via a partial defence.827
10.40Partial defences also reduce complex issues to binary inquiries. They require a jury to decide whether a defendant fits the criteria for mitigation as a “yes or no” question. This may mean mitigating circumstances are excluded from consideration at sentencing, if a jury considers the defendant does not quite come within the partial defence,828 or that “undesirable constraints” are placed on the presentation of evidence at trial,829 partly because trials are adversarial and set up to “generate a ‘winner’ and a ‘loser’”.830 Issues that turn on matters of degree are therefore not well served,831 and there is a strong argument that it is preferable for evidence of mitigating circumstances to be dealt with through the more inquisitorial and holistic sentencing process.832 As the Law Commission of England and Wales has said:833

By making evidence of diminished responsibility relevant to verdict, when (as in cases of second degree murder) it could simply be made relevant to sentence, one would needlessly force experts to distort the relevance of their evidence. Likewise, by making evidence of provocation relevant to verdict, one forces the jury to work with only a partial picture of the context in which the provocation was alleged to have been given, a partial picture largely provided (usually uncontested) by D. These drawbacks may be something that we must live with when the verdict would otherwise entail the passing of an inappropriate mandatory sentence but they should not be tolerated outside that context.

Partial defences can have undesirable or perverse effectsTop

10.41In addition to the risk of artificially rigid presentation of evidence, partial defences can have other undesirable effects. One, which we have noted, is the risk of compromise pleas and verdicts. Another is complexity for juries, which, in homicide cases, must in any event grapple with difficult concepts and evidence.834
10.42In the present context, two additional potential perversities should be noted. First, partial defences can undermine the operation of self-defence. This was noted by the Victorian Department of Justice when it reviewed the operation, and recommended repeal, of defensive homicide in that jurisdiction. The risk has also been acknowledged by other law reform bodies.835 Second, partial defences can lead to unintended consequences, particularly the excusing of conduct by “undeserving” defendants. Victoria’s defensive homicide is a clear example of this in practice – it was primarily used by violent men.836
820The co-extensiveness of partial defences and the mandatory penalty for murder was noted in Law Commission of England and Wales, above n 797, at 48–49; Law Reform Commission of Ireland Defences in Criminal Law (LRC 95, 2009) at 112; Select Committee on the Partial Defence of Provocation, above n 804, at ch 2; Tasmania Law Reform Institute Review of the Law Relating to Self-defence (Final Report No 20, 2015), at 53 and 71; Queensland Law Reform Commission A review of the excuse of accident and the defence of provocation (Report No 64, September 2008), at 500; Victorian Law Reform Commission, above n 794, at xx, 11, and 241; Victoria Department of Justice, above n 782, at 17; and Law Reform Commission of Western Australia, above n 782, at 5–6. Among jurisdictions to have abolished mandatory sentencing but retained (and in some cases reformed) or reintroduced partial defences (New South Wales, Western Australia and the Australian Capital Territory), New South Wales and Western Australia have identified particular reasons for doing so. The New South Wales Select Committee on the Partial Defence of Provocation accepted there was a case for abolition but, unable to reach a consensus and without sufficient information to enable a clear recommendation on how self-defence could be reformed to accommodate victims of family violence, did not recommend abolition but did recommend a review of homicide and defences after five years and that recommendation has been accepted (Select Committee on the Partial Defence of Provocation, above n 804, at 87 and 209). In Western Australia, the Law Reform Commission noted that mandatory murder sentencing “has provided one of the strongest justifications for the partial defence of provocation”. The Commission considered no partial defences should be retained or introduced “unless the circumstances giving rise to the defence always demonstrate reduced culpability” but found that excessive self-defence met this test (Law Reform Commission of Western Australia, above n 782, at ch 4.)
821Law Commission of England and Wales, above n 797, at 43–44; and Queensland Law Reform Commission, above n 820, at 9–10.
822Ashworth and Horder, above n 783, at 250.
823Law Commission of England and Wales, above n 797, at 48.
824Jeremy Horder Excusing Crime (Oxford University Press, Oxford, 2004) at 143–146; and Lacey, above n 795, at 120. But compare Law Commission Some Criminal Defences with Particular Reference to Battered Defendants (NZLC R73, 2001) at 41: “The argument for jury participation in determining levels of culpability should logically extend to all crimes and not be confined to murder. For good reason this has never been suggested. Instead, the task of crafting penalty to fit blameworthiness has long been the daily diet of judges.” The possibility of an expanded partial defence model is obviously beyond our remit, although we would note it is relevant, in this connection, that homicides are a small number of all violent offences, including those committed by victims of family violence responding to abuse.
825See for example Victor Tadros “The Homicide Ladder” (2006) 69 MLR 601 at 615.
826Law Commission, above n 792, at chs 4–6.
827At 72.
828At 82.
829Law Commission of England and Wales, above n 797, at 49. See also, discussing the partial defence of diminished responsibility, Jeremy Horder Homicide and the Politics of Law Reform (Oxford University Press, Oxford, 2012) at 233.
830Horder, above n 829, at 233.
831Horder, above n 829, at 233–234; Law Commission of England and Wales, above n 797, at 49; and Victorian Law Reform Commission, above n 794, at 241.
832Horder, above n 829, at 234.
833Law Commission of England and Wales, above n 797, at 49.
834At 49. See also Victoria Department of Justice, above n 782, at vii.
835Law Reform Commission of Western Australia, above n 782, at 294; and Tasmania Law Reform Institute, above n 820, at 71.
836Victoria Department of Justice, above n 782, at viii.