Leaders from around the world participated in a remote global climate summit Thursday, arranged by the Biden administration. It was a remarkable break with the recent past — every world leader of consequence attended, including Russia's Vladimir Putin and China's Xi Jinping. Every single one promised at least some kind of action on climate, some very aggressive.

The summit was part of Biden's bid to reestablish American global climate leadership. But while it was no doubt a profound relief to see a regular politician at the U.S. helm instead of a game show lunatic, the rest of the world would be fools to trust American commitment or follow-through on climate. A crackpot climate denier could easily be the next president, and even Biden and his party are not taking the problem seriously enough.

Looming over the summit was the shadow of Donald Trump, who as president abrogated as much of American climate policy as he could. His administration pulled the country out of the Paris climate accords, rolled back dozens of environmental regulations, and clumsily attempted to subsidize coal power plants to keep them from being bankrupted by cheap wind and solar (a sort of "brown new deal" as it were, though thankfully it did not work).

The United States is not going to find it easy to live down the Trump years. Not only was he appallingly backward on climate, he also continues to lead a party that largely rejects the basic science of climate change, and categorically rejects doing anything serious about it. Trump's glaringly obvious incompetence and irresponsibility deeply alarmed countries around the world and though America, like any country, has had its share of goofball presidents, Trump was in a class by himself. He made Silvio Berlusconi look like Pericles.

No other major party in the rich world is as rotten as the Republican Party, and few are in the developing world. The world leaders at the summit represent parties that are all over the political spectrum — from Canada's center-left Justin Trudeau, to Germany's center-right Angela Merkel, to Britain's right-wing Boris Johnson, to India's far-right Narendra Modi. These people have their problems, some of them very bad. But none of them are delusional maniacs who get their policy briefings by half-listening to right-wing televison media personalities while feuding with Bette Midler on Twitter. They all recognize the need to do something about climate change, because if one accepts the science, the threat is obvious no matter one's political complexion. Only Brazil's gleefully stupid Jair Bolsonaro bears comparison to Trump, and even he still participated in the summit and admitted the need for action (it seems he wants bribes in return for not burning down the Amazon basin).

A country that elected Donald Trump president — a blatantly corrupt and unhinged demagogue with literally zero prior experience — cannot be trusted not to do something similar in future. Republicans have a solid chance to win the 2022 midterms, or the 2024 presidential election, or they may simply steal those elections outright, in which case the door to new climate legislation will be closed. The U.S. can't be a global leader if the world is constantly waiting on tenterhooks to see if the lunatic party takes command once more, perhaps by establishing a permanent dictatorship. As Adam Tooze writes in The New Statesman, "Without broader societal agreement, each U.S. election will be a heart-stopping moment of potential derailment."

However, even if Democrats do somehow manage to hold on to national power indefinitely, Biden's climate ambitions are still far short of what is needed to halve emissions by 2030 and reach carbon neutrality by 2050. Domestically, his infrastructure bill would invest only about $1.3 trillion in climate policy directly over 10 years — which is maybe 10-20 percent of what it would take to meet those goals. Nor would the bill start the vitally-needed overhaul of the American built environment to reduce wasteful car dependency; while it has some money for transit, it has more than twice as much for electric cars. Nor does Biden propose to set up any international investment funds or other mechanisms to help poorer countries leapfrog fossil fuels, which is even more important given that the U.S. only produces about 13 percent of greenhouse gas emissions today.

Moreover, it is not at all guaranteed that this proposal will actually make it through Congress. The Democratic swing votes in the Senate have raised various objections, and have so far been unwilling to get rid of the Senate filibuster to allow legislation. At a minimum, they will likely trim some of Biden's ideas. Meanwhile, Republican cranks in red states are doing all they can to undermine Biden's agenda before it has even passed.

In short, America simply can't be trusted on climate change. One of two U.S. parties is an authoritarian menace that views fossil fuels as just another way to own the libs, and our anachronistic political institutions are so dysfunctional that at the best of times it's barely possible to pass anything, even to address a problem that is a dire threat to our own health and security. Until that changes, the world is just going to have to hope that we don't foul up the global effort to save human society from unchecked warming.