Betsy DeVos

WASHINGTON — The Senate is poised to confirm President Donald Trump's nominee for education secretary by the narrowest possible margin, with Vice President Mike Pence expected to break a 50-50 tie.

The vote planned around noon today comes after an all-night speaking marathon by Democrats on the Senate floor, in a show of opposition to the nominee, Betsy DeVos. She is a wealthy GOP donor who has devoted herself to boosting alternatives to public education, sparking concerns that she won't be a strong champion for the public school systems.

Two GOP senators, Susan Collins of Maine and Lisa Murkowski of Alaska, have announced plans to oppose DeVos in a Senate split 52-48 between Republicans and Democrats. That will leave her with a tie vote if all other Republicans support her and all Democrats oppose her as expected, and will require Pence to put her over the top. A vice president breaking a tie on a Cabinet nomination would be a first, according to the Senate historian's office.

The chamber went to brief, quorum calls as senator after senator completed his or her remarks and yielded the floor to a colleague. And a lone Republican senator, South Carolina's Time Scott, went to the floor to speak, as well, arguing that lawmakers' focus should be not on DeVos, but on ways to improve the education system.

“Mrs. DeVos demonstrated a complete lack of experience in, knowledge of and support for public education. She was unable to address basic issues that any New Hampshire school board member could discuss fluently,” said Sen. Maggie Hassan, D-N.H.

But Republicans accused Democrats of slow-walking DeVos and other qualified nominees to placate liberal base voters.