Donald Trump is facing impeachment, and a single phone call seems to have tipped the balance. During a conversation in July with the Ukrainian president, Volodymyr Zelenskiy, he asked for help in the investigation of his likely opponent in 2020, Joe Biden, whose son had business dealings in the country. On Tuesday, Nancy Pelosi announced that impeachment proceedings would finally begin.

But the release of the conversation summary or “memcon” between Trump and Zelenskiy on Wednesday left things a little hazier than expected.

Trump did ask for a favour, but it was for help in his obsessive quest to prove that he won the presidency fair and square. And while he later raised the prospect of an investigation into Biden, at no time did he dangle military contracts he had put on hold as an inducement. Meanwhile, Zelenskiy was more interested in possible future deals. There was a request from Trump for a quo – but no quid, exactly.

If the summary is accurate, what we are left with is not savoury, but neither is it definitive. It has nonetheless set in train another burst of excited commentary. What this excitement really represents is a further round in the dramatic cycle of argument about the meaning of Trump’s 2016 electoral victory.

For liberal and conservative centrists, inured to taking turns in power for decades, Trump’s rise in the Republican party and his success in beating Hillary Clinton within the appalling rules of the American game was the real affront. Blindsided by their ejection by an incoherent nonentity and sexual predator, this coalition of long-governing elites, from liberal technocrats to “never-Trump” conservatives, has declared war on the president, embracing any bad pretext or good reason to call for his early ouster.

There are certainly many reasons to wish Trump out of office. He is incompetent and inflammatory, and his policies are racist and anti-poor. But behind the stance of permanent alarm and outrage adopted by the political establishment is a strong sense that what really irks them is that US democracy, such as it is, has toppled them from power. And after pining for so long for Robert Mueller’s investigation to be their redemption, they have now pinned their hopes on a “memcon ex machina”.

The trouble from the beginning, and one reason for the constant repetition of the drama, is that Trump’s very conquest of the Republican party meant it was always going to be nearly impossible to convince enough members of Congress to put this presidency down early. For every chorus of dismay and shock from never-Trump centrists there is an always-Trump faction prepared to excuse him when he comes near the line of malfeasance or crosses over it – and the chorus knows it. Both sides have deserved one another at every stage.

For all their appeals to enduring moral values, whether US exceptionalism or legal principle, the centrists are deploying a transparent strategy to return to power. Trump’s shambolic presidency somehow seems less unsavoury than the fact that neither of these sides are able to admit how massively his election signified the failure of their policies, from endless war to economic inequality.

Leftwing members of Congress such as Alexandria Ocasio-Cortez and Bernie Sanders have long been in favour of impeaching Trump. But they have not made it a daily obsession. Even as Washington teemed with talking points about the phone call, Ocasio-Cortez introduced a bold plan to fight poverty; Sanders proposed a new wealth tax the day before.

Progressives are right to worry that what matters most is not whether Trump committed an “impeachable offence” (which means no more than that enough members of the House of Representatives will vote to indict him), but instead what political vision Democrats can rally behind to win the country, rigged system and all. Given the importance of that question, the current debate about whether to impeach Trump, for all the melodrama around it now, pales in comparison.

Centrists simply want to return to the status quo interrupted by Trump, their reputations laundered by their courageous opposition to his mercurial reign, and their policies restored to credibility. Meanwhile, rightwing Republicans hope to benefit from his ascendancy, doubling down on tax cuts. No wonder progressives’ greatest fear is allowing the first group to return to the failed policies that produced Trump himself, and the second to capitalise on his rise to entrench their rule indefinitely.

Al Green, a Democratic congressman from Texas who was a lonely early proponent of impeaching Trump, commented the other day that his approach was vital precisely because it would help to win the next election. In his press conference on Wednesday, the president jeered in return. Trumpeting his own success – however unearned – in promoting economic growth, he interpreted impeachment as the strategy of a party that has nothing else to offer. “All of these people focusing on the witch-hunt because they can’t beat us at the ballot,” he exclaimed with some delight.

Who is right – Green or Trump? The Ukraine affair shows that the biggest risk to the American people is that centrists link impeachment to a reinstatement of one set of failed prescriptions, while the right repulses the attempt to oust the president and rules under equally dead-end policies. And it shows that progressives must link opposition to Trump to a broader strategy to bring the country a convincing new politics of their own.