Story highlights Betsy DeVos is expected to win Senate confirmation Tuesday but Democrats are still fighting

At least one more Republican senator would have to vote against DeVos

(CNN) Democrats are mounting a 24-hour blitz to try and sink at least one nomination from President Donald Trump's Cabinet, attacking education secretary nominee Betsy DeVos a day before her confirmation vote.

Democratic senators promised to stay up all night debating DeVos early into Tuesday morning and also took to Twitter to urge residents to light up Senate phonelines. But Republicans are still expected to narrowly win her approval, with Vice President Mike Pence set to cast the first the tie-breaking vote in history for a Cabinet appointment.

The DeVos fight has become emblematic of the knock-down brawls that Democrats have set for almost all of Trump's top nominees -- dragging out, but ultimately unable to stop their approval.

"The American people are speaking in one loud voice against this nominee. I've had people come up to me and say 'I voted for Donald Trump, but I want you to vote against this nominee,'" Senate Democratic Leader Chuck Schumer said Monday, kicking off the lengthy, final debate over DeVos.

The secretary for the Department of Education might not the most consequential of positions inside the Trump administration, but the decision by two Republicans -- Sens. Lisa Murkowski of Alaska and Susan Collins of Maine -- to vote against her and a backlash among liberals angry at Democrats who supported other Trump nominees last month jelled over the weekend into the nastiest battle so far.

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