The former presidential candidate has some choice words for his party-mates after their handling of two members of the party.

When President Joe Biden took office, he found an ally in touting an agenda full of huge social investments: Senator Bernie Sanders.

But in the year since, despite Biden’s — and Sanders’s — pushes, those proposed social spending plans are all but dead due to a pair of centrist Democratic holdouts. It’s become a pain point for the party and the Biden administration, as the Democrats’ razor-thin majority makes it impossible to move anything forward without everyone on board.

Senators Joe Manchin and Kyrsten Sinema have emerged as the main roadblocks. Sanders has frequently sparred with Manchin, who single-handedly proclaimed that Build Back Better was “dead.” In a new interview with Vanity Fair, Sanders again lambasted Manchin and Sinema’s role in killing Build Back Better, saying they “sabotaged our efforts, what we were trying to do.”

“Ever since then, the Democratic Party has stumbled and fallen further and further behind,” Sanders told Vanity Fair’s Hunter Walker and Luppe B. Luppen.

Manchin has proclaimed that he’s “never been a liberal in any way, shape or form.” He’s repeatedly blasted Biden for high inflation, and has thrown cold water on discussing social spending before reducing the deficit.

“How you handle Manchin, how you handle Sinema and the other conservative Democrats is one of the challenges that the Democrats have got to deal with,” Sanders told Vanity Fair. “But the current strategy is an absolute political failure.”

At Biden’s 100 day mark last year, most Americans approved of his performance, and he was polling well above where former President Donald Trump during most of his term. However, his polling has since cratered, a potential red flag for the upcoming midterm elections.

His proposed Build Back Better framework would have extended monthly child tax credit payments, helped lower the costs of childcare, and put billions towards climate spending — something that got Sanders’ stamp of approval.

Biden’s stalled spending bill is hanging by a thread in the evenly-divided Senate. This week, Manchin ruled out reviving the social spending elements of the House-approved Build Back Better legislation, all but ending Democratic hopes to widen the safety net. He’s pressed for a much narrower bill centered on cutting the deficit, rolling back the GOP tax cuts, reducing prescription drug prices, and clean energy incentives.

Manchin is also now spearheading a small bipartisan group seeking to strike an agreement on climate and energy initiatives, an effort that’s raised eyebrows in his party. Many Democrats are skeptical that Republicans are willing to cut a deal on energy during a midterm election year.

For her part, Sinema has opposed increasing tax rates on rich Americans and large businesses. That complicates the negotiations for Democrats since Sinema’s chief demand conflicts with one of Manchin’s top priorities. It’s unclear how they’ll reconcile those competing interests and still clinch their votes. Senate Democrats hope to reach a deal by Memorial Day.