Sens. Susan Collins (R-Maine) and Lisa Murkowski (R-Alaska) both announced they won't back DeVos, who featured in a rough confirmation hearing two weeks ago, because of her views on the public education system. That leaves 50 Republican senators who could support her. If every member of the Democratic caucus joined Collins and Murkowski in voting no, Vice President Pence would be forced into a rare tie-breaking vote as president of the Senate.
But if another Republican senator bolts -- and some aren't committing one way or another right now -- DeVos would be headed for defeat. And history shows it's very rare for presidents with a Senate majority to see their nominees defeated. Very.
The last two Cabinet nominees to be officially defeated were defense secretary nominee John Tower in 1989 and commerce secretary nominee Lewis Strauss in 1959. Both faced a Senate majority from the other party. Tower, a nominee of Republican President George H.W. Bush, lost the vote of one liberal Republican but otherwise had the complete support of his party. Strauss, an Eisenhower appointee, was defeated by a Senate that was dominated by Democrats who didn't need a bipartisan front.
The last Cabinet nominee to be defeated thanks to losing senators from the president's own party was way back in 1925, when Calvin Coolidge's selection of Charles B. Warren for attorney general was rejected by both Democrats and some liberal Republicans.
The vote took place in the aftermath of the Teapot Dome scandal, and Warren was thought to be too closely allied with the sugar industry and its unfair practices. In the end, 31 Democrats and one third-party senator joined nine Republicans to narrowly defeat Warren's nomination, 41-39. All 39 "yea" votes for Warren come from Republicans.
Of course, it's much more common for Cabinet nominees facing rejection to be withdrawn than actually face a vote they will lose. But even then, it's been rare that this was the result of bipartisan opposition; more often it's been the result of an emerging scandal or the opposition party having a Senate majority.
Ronald Reagan in 1987 withdrew Robert Gates's nomination to be CIA director amid bipartisan grilling about the Iran-Contra affair, which happened when Gates was deputy director of the CIA. Democrats alone could have stopped his nomination though, given they had a 10-seat majority. Gates was confirmed to the same post in 1991 after being nominated by George H.W. Bush.
Other withdrawals in recent decades had more to do with scandal rather than bipartisan reservations. The tax problems of former Senate majority leader Tom Daschle (D-S.D.) derailed his nomination to be health and human services secretary in 2009. Conflicts of interest marred Bill Richardson's nomination to be commerce secretary that same year. During the Bush administration, 2004 homeland security secretary nominee Bernard Kerik and 2001 Labor secretary nominee Linda Chavez both succumbed to questions about ties to undocumented immigrants. Bill Clinton's pick for attorney general in 1993, Zoe Baird, was withdrawn amid similar questions.
Clinton's veterans affairs secretary nominee, Hershel Gober, in 1997 faced questions about a four-year-old accusation of sexual misconduct. His CIA director nominee that same year, Anthony Lake, drew fierce opposition from Republicans, but not Democrats. The only other nominee who was withdrawn in the 20th century was Robert C. Wood to be Lyndon Johnson's housing and urban development secretary. The nomination was never reported to committee.
So basically, since the dawn of the 20th century, we've seen a bipartisan group of senators take down a president's Cabinet nominee precisely once.