It is the hope of every rich megalomaniac that they will “leave a legacy”. David Koch, who died last week aged 79, left a significant legacy indeed. In fact, along with his brother Charles, he can probably claim to have changed the world. Unfortunately, he changed it by setting it on fire.

It’s hard to describe just what a negative force the Koch brothers have been in United States politics over the past several decades. They have used every means at their disposal to subvert democracy. They funded academic posts, thinktanks, lobbying groups, fake grassroots operations, and political campaigns. They used their tremendous wealth to push a radically far-right economic vision in which government protections and welfare programs would essentially cease to exist. They may even have been directly responsible for the election of Donald Trump, the Koch-backed Americans For Prosperity having hired 650 staffers to make millions of phone calls and knock on tens of thousands of doors in Wisconsin and Michigan during the 2016 election.

The Koch brothers profited handsomely from fossil fuels, and had a strong hand in muddying the debate around global warming, having spent more than ExxonMobil on funding climate denial. David Koch himself, asked whether climate change was real, would say only that “climate does fluctuate”. Carbon regulation posed a significant financial threat to the Kochs, and they supported “perhaps the earliest known organized conference of climate-change deniers, which gathered just as the scientific consensus on the issue was beginning to gel”. They helped to derail efforts at regulating carbon, and Kert Davies, the founder and director of Climate Investigations Center, has concluded that “you’d have a carbon tax, or something better, today, if not for the Kochs. They stopped anything from happening back when there was still time.” There may be planet-wide consequences to the political meddling of these two men.

David Koch has now left this earth, while the rest of us are still here to clean up his mess

The effort to prevent action on climate shows just how fraudulent the Koch Brothers’ professed love for “freedom” has been. The brothers presented themselves as “libertarians” who simply believed that the best way to advance human prosperity was a “free” market and the protection of private property rights. In reality, the only private property rights they cared about were their own. Nothing could be more destructive to private property than climate change, which threatens to create tens of millions of climate refugees around the world. These are people who will lose everything they have. If property rights were respected, climate-destroying companies like Koch Industries would owe a fortune in compensatory damages to their victims. A functioning market would heavily tax carbon, in order to account for the harm it does.

The Kochs, then, were never trying to advance the cause of “freedom,” or even the free market. In Dark Money, Jane Mayer documents a number of instances in which Koch Industries shamelessly polluted the environment, then tried to stymie the legal process in order to avoid paying damages, and “repeatedly lied … to avoid penalties”. Pollution is an infringement on the property rights of the people being polluted, and it was the Kochs who tried to keep those rights from being enforced. Koch organizations funded “Right To Work” initiatives that pushed restrictions on union contracts, even though Milton Friedman himself acknowledged that restricting the right to contract conflicted with libertarian principles. Similarly, despite the brothers’ professed support for immigration reform, Koch-backed organizations supported harshly anti-immigrant legislators. What could be a bigger distortion of the “free market” than restricting competition from immigrants? Ultimately, this brand of libertarianism is really just plutocracy. The Koch Brothers have always believed that rich people had the right to rule over everyone else, democracy be damned.

Defenders of the Kochs will point to their charitable giving. David Koch gave large sums of money to cancer research and the ballet. Of course, there is a certain element of self-interest to these donations: Koch himself suffered from cancer and enjoyed ballet. Having wealthy people’s personal preferences govern funding decisions is a bad model for social spending – it means that ailments of the poor will go unaddressed. But the Kochs were also consciously trying to improve their public image. Because their plutocratic politics was so unpopular, the Kochs were advised to appear more socially aware and benevolent. At one conference, Arthur Brooks of the American Enterprise Institute advised that Koch initiatives should be framed as matters of “fairness”.

“‘I know it makes you sick to think of that word, ‘fairness,’” Brooks said. Alas, the American public believes that “it’s right to help the vulnerable”. The Kochs themselves did not believe that, but they went along with it, making a public show of their support for criminal justice reform and donating a large sum of money to the United Negro College Fund for black students to study “how entrepreneurship, economics, and innovation contribute to well-being”.

Theodore Roosevelt certainly had it right when he said of rich philanthropists that “no amount of charities in spending such fortunes can compensate in any way for the misconduct in acquiring them”. That’s especially true in the case of the Koch Brothers, whose wealth is built on an industry that threatens the lives of people around the world. David Koch embodied all of the worst aspects of our political and economic system. He inherited a company, then used the spoils to try to manipulate American politics to destroy all of working people’s hard-earned gains (Koch wanted to eliminate Medicaid, minimum wages, and workplace safety protections). He pushed fabricated science to protect his profits, with zero regard for the consequences this would have for humanity at large. And he had the audacity to do all of this while presenting himself as a freedom-loving philanthropist.

David Koch has now left this earth, while the rest of us are still here to clean up his mess. His brother Charles lingers, and will surely try to keep up the family business of poisoning American politics. We must make sure he does not succeed, and all of humanity can look forward to the day when the Koch Brothers’ influence is nothing but an unpleasant memory.

Nathan Robinson is the editor of Current Affairs and a Guardian US columnist

• This article was amended on 15 September 2020 because it was Kert Davies, not Christopher Leonard, who said the following quote: “You’d have a carbon tax, or something better, today, if not for the Kochs. They stopped anything from happening back when there was still time.” This has been corrected.