The first indication that Pompeo could face a tricky confirmation battle came almost immediately after Trump announced his nomination, when GOP Senator Rand Paul of Kentucky declared his opposition based on Pompeo’s previous defense of torture and support for the NSA’s government spying programs. Paul gave no indication that he relented on Pompeo when he questioned him during last week’s confirmation hearing; he jousted with the CIA director over the constitutionality of Trump’s military strikes on Syria and over the ongoing war in Afghanistan.

“My biggest problem with your nomination is I don’t think it reflects the millions of people who voted for President Trump who actually voted for him because they thought he’d be different,” Paul told him.

Republicans have just a 51-49 majority in the Senate overall, and in the Foreign Relations Committee, Paul could hold the decisive vote. If he sides with all Democrats against confirmation, Pompeo would become the first nominee for secretary of state not to win approval from the panel since it began keeping records of such votes in 1925. Interestingly, the last senior diplomatic nominee to fall short in the Foreign Relations Committee is now Trump’s national-security adviser, John Bolton. The panel rejected President George W. Bush’s nomination of Bolton to serve as U.N. ambassador in 2005, and Republicans failed to defeat a Democratic filibuster to confirm him on the floor. Bush ended up installing Bolton as a recess appointment, and he served in the post for nearly a year and a half.

Senator Robert Menendez of New Jersey, the top Democrat on the committee, has said that if Pompeo can’t win the panel’s approval, Trump should replace him with a nominee that can gain broader support. But that isn’t likely to happen. Senators in both parties expect Majority Leader Mitch McConnell to schedule a full floor vote on Pompeo’s nomination regardless of how the Foreign Relations Committee votes. If Paul and all 49 Democrats voted no, Pompeo would go down unless Senator John McCain of Arizona made an unlikely return from his months-long absence due to brain cancer. McCain hasn’t voted in the Senate at all in 2018.

But the assumption is that vulnerable Senate Democrats up for reelection in red states this fall—like Joe Manchin of West Virginia, Heidi Heitkamp of North Dakota, and Joe Donnelly of Indiana, among others—will vote to confirm Pompeo and save him, and Trump, from an embarrassing defeat. Those three voted along with 14 other Democrats to confirm him as CIA director, but they have yet to take a position on his nomination for secretary of state.

Should that happen, Pompeo would become only the second Cabinet officer on record to win confirmation by the full Senate after an unfavorable committee vote, according to the Senate Historical Office. The only other example was former Vice President Henry Wallace, who was nominated by President Franklin Roosevelt to serve as secretary of commerce in 1945 after he had dumped him as his running mate in favor of Harry Truman the year before. The last time the Senate actually rejected a presidential Cabinet nominee was in 1989, when President George H.W. Bush’s nomination of John Tower for secretary of defense went down in defeat. (Many other nominees have withdrawn once it was clear they wouldn’t secure enough votes on the floor.)