In September 2010, David and Charles Koch, the fabulously rich brothers who turned an oil and manufacturing empire inherited from their father into a cash cow for rightwing causes that would change American politics, sent out a letter to conservative power brokers inviting them to Palm Springs.

They were staging an event that was to become known as “Freedom Partners”: a twice-yearly gathering, convened in utmost secrecy, of some of the most wealthy and powerful rightwing players in the country. To attract their guests they included a brochure from a previous Koch gathering in Aspen, where the elite attendees had sat around in mountainous splendor discussing, among other issues: “Is America on the Road to Serfdom?”

The most intriguing part of the brochure was a roll-call of names of those lured to previous “Freedom Partner” gatherings. It included the current vice-president, Mike Pence; the Wisconsin politician Paul Ryan, who would go on to become speaker of the House of Representatives; super-donors such as the hedge fund manager Ken Griffin, and most intriguingly of all two conservative justices of the US supreme court, Clarence Thomas and the late Antonin Scalia.

That the brothers could bring under one roof top politicians, billionaire donors and senior judges to plot the future of America on a free-market, anti-government course illustrated the scale of their ambitions and the influence they wielded.

No wonder their sprawling network of conservative chums came to be dubbed the “Kochtopus”.

The death of David Koch, announced on Friday, severs a fraternal partnership with Charles that has been a driving force of America’s increasingly bitter partisan politics. So reviled did David and Charles become in liberal circles that “Koch brothers” became a catchphrase for the insidious influence of big money.

As Lisa Graves, director of a new digital archive, Kochdocs.org, that tracks the brothers’ record, put it: “A substantial part of David Koch’s legacy was the utter distortion of American democracy, which should be based on one person, one vote but was grossly twisted when he used his vast wealth to buy himself an influence that was out of all proportion.”

Many date the rise of the Kochs to 2010, the year in which the highly contentious landmark supreme court ruling Citizens United (approved by both Scalia and Thomas) opened the floodgates to corporate money in elections. The Kochs leveraged their affiliated organizations to raise well over $100m in the 2012 presidential election alone – a clear indication of the damage wrought by the judgment and the advantage they reaped from it.

(Fun fact: it is well known that the Koch brothers support Republican candidates, but it is less well known that over two decades they spent not a single dime on any Democrat.)

But the roots of the brothers’ impact go further back. Their father, Fred Koch, who died in 1967, was a rightwing firebrand and extreme anti-communist. He passed down to his sons an obsession with the socialist threat to American greatness that is eerily reminiscent of one of Donald Trump’s core re-election themes for the 2020 race.

They also inherited Fred’s family business, Koch Industries, headquartered in Wichita, Kansas, which they expanded and diversified into an empire that spans lumber businesses, carpets and paper mills and has become the second-largest privately owned company in the US. Koch Industries can also claim the distinction of being one of the country’s most highly polluting companies, behind only ExxonMobil and American Electric Power.

It is a seminal quality of the Kochs’ politics that it is virtually impossible to separate out their personal convictions from their pragmatic desire to advance their personal and corporate fortunes. Where do their ideological beliefs end and private greed begin?

Even in his 20s, David Koch was attending a “Freedom School” where he learnt about “anarcho-capitalism” and the virtues of small government and abolishing taxes. Low taxes would be personally appealing to someone with a vast and growing fortune like his.

David Koch in Washington in 2011. Photograph: Chip Somodevilla/Getty Images

So too would countering any effort to penalize toxic corporations in the fight against climate change. By Greenpeace’s reckoning, in the 20 years to 2017, the Kochs ploughed about $127m into 92 groups that were involved in rebuffing climate crisis solutions.

“David Koch won’t live to see the worst of climate change but the legacy of denial and the intensified delay caused by his funding will live on,” said Kert Davies, director of the Climate Investigation Center. “It is clear that he provided life support to the denial machine.”

Koch’s similarly self-interested desire to drive government out of the US economy by undermining regulations and slashing corporate taxes started to firm up in 1980, when he stood as the Libertarian party’s vice-presidential candidate. By then, many of his other passions were also taking form, including abolishing social security and rolling back welfare benefits for low-income Americans.

In 1977 he supported Charles in founding and funding the libertarian Cato Institute. But it was not until 2004 that the true embodiment of the brothers’ desire to reshape the country was born: Americans for Prosperity. “AFP was the vehicle for their dreams of channeling their politics into what would become almost a shadow Republican party,” Graves said.

Through AFP, the Kochs spawned a nationwide web of impassioned conservative volunteers, empowered by the new voter technology they supported through the political data firm i360. Among the key targets of their campaigning: the Affordable Care Act, known as Obamacare, which brought healthcare to millions of Americans but which the Kochs saw as big government interference. But it also took on climate crisis regulations, public education and taxes and championed the nascent 2010 Tea Party movement.

In the past couple of years, David Koch, and his arguably even more ideologically driven brother Charles, have perhaps been less prevalent on the right as their political pulling power has appeared to wane a little. That might be in part due to David’s deteriorating health as he began to lose his 20-year battle with prostate cancer, stepping down from all his business and political roles last year.

It is also in large part due to the advent of Trump. There has been much discussion in recent months about the very public spat between the president and the Koch brothers, with the Kochs calling Trump’s trade tariffs “detrimental” and Trump lashing back that the billionaires were “a total joke”.

With the exception of trade policy, which is anathema to the free market Koch view of the world, the truth about Trump, though, is that he has adopted many of the rightwing postures the Kochs have long espoused.

Take Trump’s 2017 tax cuts, which cost $1.5tn to the benefit of the rich above all others. The cuts follow a script very similar to the plan put forward by the Koch brothers – which helps explain why they went on to spend more than $20m promoting the legislation.

But then, in the calculation of Americans for Tax Fairness, David Koch and Charles would have saved more than $1bn themselves in income tax.

In David Koch’s passing on Friday America has lost a lion of conservatism whose backing for ultra-rightwing causes was cherished by fellow billionaires, corporations, polluters – even some supreme court justices. But members of that elite club of “Freedom Partners” should find solace in the thought that – though David Koch will no longer be there to greet them at their secretive retreats – his influence is still very present, right there in the White House.