Senate Dems Hold All-Night Floor Session in Effort to Stop DeVos

— -- Senate Democrats stayed up for an all-night floor session to make their case against President Donald Trump's Secretary of Education nominee Betsy DeVos .

Starting on Monday afternoon, the Democrats vowed to talk on the Senate floor for 24-hours with the hopes of persuading one more Republican to vote against DeVos, which could tip the balance against her but is unlikely to happen.

Overnight, many of the Senators used their time on the floor to reiterate their concerns about DeVos, while others decided to read letters and emails from constituents.

DeVos stirred up strong opposition from teachers’ unions and all 48 Senate Democrats, all of whom say they will vote against her. Two moderate Republicans say they plan to vote to block her nomination, but she still has the support of 50 Republican senators as well as Vice President Mike Pence, who can cast the tie-breaking vote.

For procedural reasons, the earliest the Senate may vote on her confirmation is Tuesday at noon, so Democrats can eat up the remaining hours until the vote by railing against her on the Senate floor.

Sen. Joe Donnelly shared multiple anecdotes from "people all across Indiana," including a letter that he said was from a former teacher who was consumed with "fear, fury and grief" over DeVos' confirmation hearings.

Sens. Kamala Harris of California and Cory Booker of New Jersey both argued that DeVos is a threat to the public education system.

"We have to have people that understand that public education is a right for everyone," Booker said.

"[I]t is clear from her testimony that Betsy DeVos has not done her homework," Harris said.

Sen. Sheldon Whitehouse of Rhode Island took his criticism a step further and questioned the billionaire philanthropist's ability to "do a fair job."

Sen. Michael Bennet of Colorado called DeVos' nomination "an insult to school children and their families."

GOP Sens. Susan Collins and Lisa Murkowski have announced their intention to vote against DeVos, which would leave her with the bare minimum of 50 votes in her favor.

Vice President Mike Pence has said he will use his authority as the president of the Senate to cast a tie-breaking vote in favor of DeVos, but Democrats vowed to use their remaining hours of floor time in protest before the ballots are cast.

ABC News' Ali Rogin and Rayquan Taylor contributed to this report.