Betsy DeVos Vote: What happens if the Senate splits 50-50 on Trump's education secretary nominee?

The Senate is expected to vote Tuesday on Betsy DeVos, President Donald Trump's pick for secretary of education, following a 24-hour protest by Democrats on the Senate floor.

DeVos, a billionaire charter school advocate, was called "incompetent" and an "amateur" by Democrats during their all-nighterTwo Republicans have vowed to vote against her confirmation, likely splitting the vote 50-50. 

This means Vice President Mike Pence will have to break the tie as president of the Senate; he will almost certainly vote to confirm DeVos.

Protesters on Capitol Hill demonstrate against Betsy DeVos on Monday.

Prior to Tuesday's vote, there have been 244 occasions on which the vice president has had to break a Senate tie. The last time was in 2008, when Dick Cheney broke a tie on a budget resolution. Joe Biden never cast a tie-breaking vote. 

So while DeVos is likely to be confirmed, the rare tie-breaking vote makes her path to the Cabinet unusually rocky.