The US Supreme Court justice Antonin Scalia is dead, and not before time. The co-author of some of the dodgiest court opinions since Judge Taney's in Dred Scott v. Sandford, Scalia was duly hymned on Saturday night's debate in South Carolina by the self-avowed psychopaths – Ted Cruz has vowed to make the Middle East 'glow' with US bombs; Donald Trump’s problem with waterboarding is that the torture doesn't go far enough – slugging it out for the Republican presidential nomination. Scalia's judicial opinions reveal a mind whose fixation with the jurisprudential genetic fallacy known as 'originalism' betrayed his embrace of legal ancestor worship in a peculiarly pure form. It seems fittingly bizarre that he died on a quail hunting trip (his Supreme Court crony Clarence Thomas noted that Scalia 'loves killing unarmed animals').

'De mortuis nil nisi veritas' is a useful rule of thumb for commentary when the mighty die, and Scalia was certainly one of those in his own mind. He unflinchingly opposed marriage equality. He was still at it last year, dissenting from the court's decision to make same-sex marriage legal throughout the States on the ground that liberalising marriage law 'robs the people of... the freedom to govern themselves', posing a 'threat to American democracy' because 'today's decree says that my Ruler, and the Ruler of 320 million Americans coast-to-coast, is a majority of the nine lawyers on the Supreme Court' – a role that he seemed content with when he was one of those in the majority.

Scalia repeatedly blocked federal action on climate change. There he found his jurisdiction ample enough to define the air. In a dissent in Massachusetts v. EPA in 2007, Scalia opposed the plaintiff's claim that CO2 is a pollutant causing global warming. Scalia found that air, as mentioned in the 1963 Clean Air Act, includes only 'air near the surface of the earth', not 'the upper reaches of the atmosphere', where 'the build-up of CO2 and other greenhouse gases... is alleged to be causing global climate change.'

Scalia helped deliver the 2000 presidential election to George W. Bush by guillotining the Florida recount. Here, again, Scalia seems not to have been cowed by thoughts of limits on the court's powers. More striking was his ad hoc invocation of the Fourteenth Amendment to argue that the recount should be stalled because Florida counties' different methods of counting ballots would violate the equal protection clause – something that applied only to the recount, and not to the state's elections generally. Dubya duly walked down Pennsylvania Avenue the following month.

In the 2008 case of DC v. Heller, Scalia applied originalism to offer a wide reading of assault-rifle owners' Second Amendment rights. He decided the amendment's prefatory clause about militias was irrelevant to the operative clause's meaning as understood by the Founders, which turned out to include protecting the personal use of firearms such as semi-automatic rifles whose invention lay well in the future. Boldly eschewing engagement with what the Founders had actually written, Scalia decided that they were talking about weapons in 'common use', not that this phrase figures in the amendment (semi-automatic rifles comprise around 2 per cent of privately owned firearms). Presumably the revered Founders had guns like muskets in mind, but where as often they don't say anything explicit, originalism comes into its own: they say whatever the medium who tongues their thoughts say they said.

Scalia's most pernicious opinion may prove to be Citizens United v. Federal Election Commission from 2010. That declared that the First Amendment extends to corporations. Under the Citizens United decision, bungs from SuperPacs, the consortia formed to buy elections for private corporate interests, are protected 'speech'. Last month Hank Greenberg, the former head of AIG, gave $10 million to the SuperPac supporting Jeb Bush. Greenberg crashed his firm with junk securities and then bleated that the $180 billion federal bailout was paltry (his AIG shares were 'virtually worthless', he complained in 2008, 'about 100 million dollars'). So, thanks to Scalia, public money paid out by George W. Bush's administration is now bankrolling his brother's faltering White House bid.

Citizens United came to court when the lobbying group of that name appealed against a ban on airing Hillary: The Movie (an attack on Clinton) during the 2008 election campaign; its specific target was clause §203 of the 'McCain-Feingold' Act of 2002 which prohibited 'electioneering communications' in the sixty days before a general election. Earlier, in an indication of how it really valued free speech, Citizens United had tried to use §203 to gag the broadcast of a trailer for Michael Moore's documentary Fahrenheit 9/11 during the 2004 election cycle. When it later decided to push for the Supreme Court to rule §203 unconstitutional, Citizens United found Scalia compliant. His legal case – that 18th-century Englishmen didn't dislike corporations as much as some people think – was uninhibited by the Founders' failure to say anything at all about corporations in the Constitution.

At the start of Saturday's GOP brawl, soon after Scalia's death became public, the candidates stood in righteous silence for a moment (presumably a whole minute would have been beyond Trump). And rightly: a friend of guns, pollution and big money buying elections, Scalia did the job for which Reagan installed him.