Story highlights Two GOP senators have already said they will oppose DeVos' nomination

The Senate will vote Monday; VP Mike Pence would be needed to break a tie and approve De Vos as the secretary of education

Washington (CNN) Betsy DeVos, President Donald Trump's pick to lead the Department of Education, is personally lobbying senators ahead of what could be her historically close confirmation vote Monday.

Republican Sens. Lisa Murkowski of Alaska and Susan Collins of Maine both announced earlier this week that they would break with their party and vote against DeVos' confirmation. The announcements sent shock waves across Capitol Hill and kicked the lobbying effort on DeVos' behalf into overdrive.

DeVos, her spokesman Greg McNeilly said Friday, is reaching out to lawmakers and has been told by 50 Republican senators that they will vote for her Monday.

Should all 50 Republicans keep to their word and back DeVos, Vice President Mike Pence will be required to break the tie in the Senate and approve Trump's education secretary pick.

The Historian of the United States Senate, the official record keeper of the legislative body, said they have yet to find a case where the Vice President was required to break a tie on a cabinet nomination.

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