Democratic infighting and distrust combined to tarnish a likely victory Thursday.

President Biden is in Europe without clear confirmation that his key piece of social spending legislation will pass — despite a last minute trip to the Capitol Thursday morning to make the case for a $1.75 trillion framework.

The White House and Democrats will argue that, so long as the legislation passes eventually, the horse-trading that has marred the process will be forgotten.

But even if that proves true, it doesn’t change the fact that the party’s roiling internal tensions are causing serious problems here and now.

Speaker Nancy Pelosi (D-Calif.) early Thursday evening delayed a vote on a separate $1 trillion infrastructure measure, despite having pushed hard to pass the measure earlier in the day.

The delay — the second postponement for the bill — was a rare exhibition of weakness from the Speaker, who prides herself on both her vote-counting abilities and her capacity to sway recalcitrant members of her caucus.

The reasons for the impasse are numerous, but none of them are good for Democrats.

Progressives are dismayed by the scale of the cuts to the social spending bill, which have seen cherished objectives like paid family leave, tuition-free community college and a clean electricity program stricken.

At the same time, the two Democratic senators who have extracted concessions in scaling back the original proposal — Sens. Joe Manchin (D-W.Va.) and Kyrsten Sinema (D-Ariz.) — are still vague about whether they are committed to supporting the framework that Biden has outlined.

Anger from more progressive Democrats has been simmering at Manchin and Sinema throughout the process, with some on the left openly accusing them of bad faith.

The left is not about to extend the benefit of the doubt to the duo now.

The upshot is that progressives were in no mood to back down from their position that they would not vote on the infrastructure package until they got more concrete assurances on the social spending bill.

Rep. Pramila Jayapal (D-Wash.), the head of the Congressional Progressive Caucus, reiterated in a Thursday afternoon statement that members of her group would not back one bill without the other.

Rep. Rashida Tlaib (D-Mich.), a member of the so-called "squad," told reporters she was “a ‘hell no’” to advancing infrastructure without certainty on the social spending bill.

Another "squad" member, Rep. Ayanna Pressley (D-Mass.), tweeted: “A deal is a deal. These bills move together.”

The vote delay amounted to another moral victory for the left.

But it also came as unwelcome news to Biden, who had wanted to shepherd a confirmed agreement home before departing for a transatlantic trip that will include a meeting with Pope Francis, a Group of 20 summit in Rome and a climate change conference in Glasgow, Scotland. Biden will not return to Washington until next Wednesday.

Pelosi was reported to have earlier told her caucus not to “embarrass” the president by rejecting the infrastructure bill. But the delay of the vote affirms that progressives were willing to do just that.

Biden himself had reportedly told Democrats on Capitol Hill that it was not “hyperbole to say that the House and Senate majorities, and my presidency, will be determined by what happens in the next week.”

Given the stakes involved, the lack of action is frustrating to many in the Democratic Party — even as they acknowledge the misgivings about the cuts to the big bill.

“The biggest obstacle that Democrats are facing right now is the lack of progress,” said Tad Devine, a strategist who held a senior role on Sen. Bernie Sanders’s (I-Vt.) 2016 presidential bid. “If they make progress, they can begin to tell a story. The Republicans have a well-developed story, and the Democrats are negotiating something that nobody seems to understand. That’s a loser.”

The expectation on Capitol Hill is that both bills will pass eventually — perhaps sometime next week. And voices across the Democratic spectrum emphasize that such an outcome would be a significant victory.

Many Democrats fairly point out that combined infrastructure and social spending legislation amounting to almost $3 trillion is no minor matter — especially coming on top of a COVID-19 relief bill signed into law in March that was worth almost another $2 trillion.

In addition, even the pared back version of the social spending bill includes universal pre-kindergarten, an extension of a $300 per month child tax credit, an expansion of Medicare to cover hearing issues and more than $500 billion to combat climate change.

Across the party, there is a near desperation to enact the legislation so that voters can feel the benefits — or at least know those benefits are coming — before next year’s midterm elections.

Even on the left, there is an acknowledgement that incremental progress is vital.

“Progressives are in the same place that we have been, certainly since the first Bernie campaign — we have some power, and it’s growing, but it is quite limited,” said left-wing strategist Jonathan Tasini. “But the second thing is, I believe that the word ‘progressive’ means progress. ... You have to pass the bill and fight another day. It’s not over!”

The delay could also cost Democrats more than just prestige.

In Virginia, across the Potomac River from the Capitol, Democratic gubernatorial candidate Terry McAuliffe is locked in a tough fight with Republican Glenn Youngkin.

McAuliffe has pleaded with his party to pass the bills, but they may not now do so before Election Day on Tuesday. A Fox News poll released Thursday put Youngkin up 8 points in a state Biden won by 10 points a year ago.

Democrats will, in all likelihood, get their legislation in the end.

But the tremors from all the potholes they’ve hit along the way could resonate for a long time.

The Memo is a reported column by Niall Stanage.