Congress’s passage on Friday of Joe Biden’s infrastructure bill would ordinarily have been a cause for celebration. But there is a good chance it was the beginning of the end of his presidency. After all, the bill’s final days marked a new consensus around a centrist set of economic remedies, chosen out of fears of what will supposedly happen when progressives with a transformative agenda exercise too much influence on the Democratic party agenda.

Only 10 months ago, Biden came into office with great expectations – but greater terrors. Even more apparent at the start than now, Biden’s presidency has been defined by fear rather than hope. With the assault on the Capitol earlier in the month, the culmination of a four-year deathwatch for American democracy, the emergency could hardly evaporate overnight. With Donald Trump temporarily ousted, his replacement also drew 1930s comparisons. The question “is he or isn’t he?” had been asked of Biden’s predecessor for four years. To redeem the country from the fascist, was Biden going to be Franklin Roosevelt?

Like FDR, Biden led Democrats who have rightly stressed economic transformation for the sake of the poor and vulnerable but also for the angry and disaffected voters of the stagnating middle. But unlike Roosevelt, Biden’s coalition is fragile and fissures emerged to threaten his success almost from the start – fissures that broke it apart definitively last week even in the midst of Biden’s infrastructure victory.

Other causes were forced to the margins along the way. Biden subordinated even critical fixes to American democracy, like reforms of courts and elections, to the economic agenda. As for his immigration policies, which mostly resembled the disgusting ones of prior presidents, they were treated with a partisan silence, provoking rage among the few principled enough to demand fewer cruelties and restrictions no matter who is imposing them. But Biden got a pass because enough agreed with the priority to address the economic reasons for Trump’s breakthrough, which are undeniable.

Yet in comparison to Roosevelt’s first “100 days” – which saw 15 major bills and gave the early phase of every presidency its name – Biden’s first 100 days were bogged down. A Covid-19 relief and stimulus bill was passed, adding $1.9tn in emergency spending to the $2.2tn of the first such bill signed by Trump in March 2020. But the real hopes fell on the big-ticket measures for “infrastructure” and welfare that Biden resolved to pursue separately. After all, the American Rescue Plan was only meant to be a temporary stopgap for an American society beset with deeper ills even beyond those that the virus laid bare.

The game was on. At first the debate seemed to be about how costly to make the bills and how to fund them. This was especially true for the American Families Plan, which was supposed to take steps towards an American welfare state – including by making relief measures for children in earlier bills permanent. Progressives in Congress, understanding the risks, were lauded for an early victory in August, refusing to back the first narrower infrastructure bill if Democrats abandoned the second more ambitious social spending bill. Centrists tried to tag progressives as the obstructionists. But the mainstream narrative remained that by holding infrastructure hostage, progressives were wisely keeping centrists from returning to form.

Even as it became clearer and clearer that the Democratic centrist senators Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, and like-minded Democratic colleagues in the House of Representatives, were doing damage to the ambition of the bills, a breakthrough after generations of Democratic austerity and neoliberalism still seemed possible. Then came the critical event that allowed for the centrist breakthrough last week: the election for Virginia governor last Tuesday.

In an electoral shock, Republican Glenn Youngkin won – and, more important, grizzled and uncharismatic Democratic party sage Terry McAuliffe, who had once held the governor’s office, lost. Even though McAuliffe’s reputation for decades has been one of a centrist on economics – he served as Bill Clinton’s campaign chair in the 1990s – centrists scored a narrative victory. Wasn’t it because of progressive excess that voters were turning on the party? “Wokeness derails the Democrats,” one headline ran. Lawmakers in Washington scurried to marginalize progressives by passing the infrastructure bill, with some progressives voting no, and others citing promises that Democrats will still continue on to the welfare measures.

The rush to judgment was peculiar. It is not until 2022 that the Democrats will need to show something for themselves, and there was no reason to abandon the social spending plan. Suddenly, however, progressives holding tough – since some Republicans supported the infrastructure plan – were dispensable.

The new narrative was that Youngkin won because of antiracist rhetoric many Democrats have adopted, along with elites branded as “out of touch” by other elite commentators. Centrists saw a golden opportunity to call for a return to their moderation, including in containing spending.

In an extraordinary op-ed, the New York Times called for an “honest conversation” about abandoning progressive goals across the board – including the economy, where Americans demand “bipartisan solutions” that respect inflationary risks and refuse to spend very much. The truth was that Americans had gotten bipartisan neoliberalism for decades, but no matter. One Twitter commentator snarkily noted that it was hardly surprising that “the lessons from Tuesday’s election” matched the “ideological goals” neoliberal elites “had before the election and decades before that. What are the odds!”

Democrats blew by the possibility that McAuliffe’s failures were mainly his fault, and due less to “critical race theory” that allegedly was already reshaping public education than to an abandonment of parents forced to endure school closures for years (itself an economic issue). Either way, the critical error is assuming that voters rejected progressive economic policies, which are popular across the board.

Even before the events the other day, Democrats defined what was in Build Back Better – their slogan and the name of the welfare bill – downwards. Free college was stripped out early, family and medical leave – standard across industrialized democracies for decades – were killed late, and Biden kowtowed to centrists who demanded a more marketized version not just of environmental concern but of funding government across the board, as taxes hikes were reversed. With its fate no longer hostage to infrastructure, in spite of written promises from some centrists that progressives reportedly exacted at the last minute, there is no reason to be optimistic about the final bill’s fate.

An infrastructure bill for a country in decay and decline was much needed and has itself eluded Democrats for decades. Though cut in half to win acceptance, its $1tn for a grab bag of spending – much focused on transport – is nothing to trivialize. But rarely in history has a greater looming defeat been snatched from the jaws of a political victory as the other day.

In the first year of Biden’s presidency, Democrats agreed that the only alternative to barbarism is, if not socialism, some modicum of economic change. Many agreed that opening acts of Barack Obama’s administration had been fatefully insufficient. Now, despite the lessons of the Obama presidency, Republicans are set to recapture one house of Congress after two years – or both. By contrast, FDR gained seats in both houses after delivering substantive change, and won the presidency three more times.

Of course, even if progressives were to secure a welfare package and retain influence in their party, Trump – or an even more popular Republican – could still win the presidency. But this outcome is a near certainty if the Democrats return to centrist form – as seems the likeliest outcome now.

• Samuel Moyn is a professor of law and history at Yale and the author of Not Enough: Human Rights in an Unequal World