A conviction can only be "according to law", but an acquittal need not be.
We don't often mention the jury's power to return a perverse verdict acquitting a defendant. It is probably best not to mention it at all. Sometimes it is put in a way that is obviously wrong, as when a self-represented defendant submitted on appeal that it is the jury's
"... right and their primary and permanent duty, to, judge the justice and rightness of the law, and to hold all laws invalid, that are, in their opinion, unjust or oppressive, and all persons guiltless in violating or resisting the execution of such laws."
Mckee v R [2013] NZSC 122 (14 November 2013) at [8]. Naturally the Court rejected this submission.
A problem with this sort of broadside submission is that it will provoke a sweeping reaction. The Court said [9]:
"This submission is misconceived. A jury's duty is to apply the law in accordance with the judge's instructions."
More accurately, a jury's duty is to ensure that if a verdict is guilty it results from applying the law in accordance with the judge's instructions.
If the jury has applied the law in accordance with the judge's instructions, the defendant cannot appeal saying that the jury shouldn't have done that. Perversity of verdict is a matter entirely for the jury and cannot be taken up as ammunition for the defendant on appeal.
Nor can a prosecutor appeal against an acquittal on the grounds that it was perverse.
Obviously, I must point to some authority in support of my criticism that the Supreme Court was not accurate at [9]. In R v Shipley (1784), 4 Dougl. 73, 99 E.R. 774, at p. 824 Lord Mansfield said:
"It is the duty of the Judge, in all cases of general justice, to tell the jury how to do right, though they have it in their power to do wrong, which is a matter entirely between God and their own consciences."
This was cited with approval by the Supreme Court of Canada in R v Krieger [2006] SCC 47, discussed here on 27 October 2006 where I also referred to the views of Lord Devlin and Geoffrey Robertson QC.
To those dicta I add Lord Judge's speech "Jury Trials" Judicial Studies Board lecture, Belfast, 16 November 2010, available at http://www.judiciary.gov.uk/Resources/JCO/Documents/Speeches/speech-lcj-jury-trials-jsb-lecture-belfast.pdf. Lord Judge alluded there (p 2) to the power of the jury to return a perverse verdict:
"But even in a democracy, it is possible for the legislature to create potentially oppressive and unjust criminal laws. The very fact that such laws will be exposed to the scrutiny of a jury in the event of a prosecution may – and for my own purposes "may" is enough – cause the legislature to pause and reflect on whether it is wise to enact such a law. It is one small aspect of the very subtle relationships which govern the operation of our society and the well being of the community."
So yes, subtlety is everything on this point. But whether a sweeping statement like that at [9] of McKee can really abolish the power of a jury to perversely acquit may be doubted. Can the perversity of a jury's acquittal ever be eliminated? The prosecutor would need a right to appeal on the grounds that an acquittal was unreasonable, and obtaining that would be a rather ambitious law reform project, at least in a robust democracy.
[Update: In 2015 Lord Judge again referred to
perverse verdicts as constitutional safeguards against barbaric laws in a
discussion with Chief Justice Roberts on the 800th anniversary of
the sealing of the first issue of Magna Carta, available here on YouTube: view from time setting 37:58.]
