The most ambitious voting rights bill in generations seems doomed to defeat today, as Republicans in the Senate are preparing to wield the filibuster to kill the For The People Act.

Today’s vote – expected at 5:30 et – would allow debate on the bill. Even that half-measure seems destined to wither on the vine as the GOP moves in lockstep against efforts to make voting easier.

The For The People Act – passed by the House in March – would expand early voting and no-excuse absentee voting. It would curb partisan gerrymandering, unmask ‘dark money’ political contributions, and enable public funding for elections. It would also require states to adopt online and same-day registration; felons would automatically be registered upon their release from custody. Voter ID requirements would be eased.

That last provision – on voter IDs – has drawn pointed criticism from Sen. Joe Manchin, the West Virginia Democrat whose holdout vote imperils a united front on the left.

“What we are measuring, I think, is, is the Democratic Party united? We weren’t as of a couple of weeks ago,” said Jen Psaki, the White House press secretary.

Manchin could still vote for the debate, which would be a sort of moral victory – but one that falls well short of progressive goals. The left flank of the Democratic party has identified voting rights as an existential issue. They point to dozens of bills passed or proposed in GOP-led state houses that make it harder to vote. The For the People Act would be a federal cure-all that reverses that trend.

Manchin has called the legislation “too partisan.” He’s been the subject of intense pressure from within his own party. But Manchin’s a Democrat in a deep-red state; his constituents have rewarded his moderate reputation over the course of three Senate terms.

Last week, he released a voting rights framework that scales back the proposed law – particularly in the realm of campaign finance – but he agrees that early voting and absentee voting should be expanded and that gerrymandering should be reigned in.

Former President Barack Obama, a Democrat standard bearer, said yesterday that Manchin had “come up with some common-sense reforms that the majority of Americans agree with, that Democrats and Republicans can agree with.” He added that Manchin’s proposal “doesn’t have everything I’d like to see in a voting rights bill.”

Stacey Abrams, the most influential voting rights activist of her generation, has also expressed support for Manchin’s plan.

Still, Republicans seem inclined to reject – and filibuster – that watered-down proposal, too. Senate Minority Leader Mitch McConnell (R-KY) has called voting rights a left-wing “power grab.”

Politico reports that progressive activists are incensed that the White House hasn’t done more to pressure Manchin:

Indivisible founder EZRA LEVIN went on a tear about this Monday, declaring in a Twitter thread: “I have reached my WTF moment with Biden on this.” The progressive grassroots leader said BARACK OBAMA “did a live debate with House GOP on the ACA,” BILL CLINTON “gave 18 speeches on NAFTA and deputized [AL] GORE to debate ROSS PEROT on it,” and DONALD TRUMP and GEORGE W. BUSH “were all tax cuts all the time.”

“Where is the president?” he asked. “Is saving democracy a priority for this Administration or not? I don’t want to see some tepid public statement. We need to see the President and VP using the full force of their bully pulpit to lead.”