McCarthy has served as House Minority Leader since 2019 and previously served as the general House GOP leader since 2014 under Speakers John Boehner and Paul Ryan. With Republicans set to take the House majority in the wake of the recent midterm elections, McCarthy is currently running to be the next Speaker of the House, but the party’s razor-thin majority and margin and dissent from its far-right flank have put his prospects in jeopardy.

With the House breakdown set to be 222-213 in favor of Republicans, McCarthy could only lose five votes from his own party before dipping under the 218 needed to become Speaker. The dissent against him has been primarily led by the House Freedom Caucus and has included the likes of Florida’s Matt Gaetz and Pennsylvania’s Scott Perry, who have accused McCarthy of not being sufficiently conservative and being too beholden to status-quo politics.

After the 118th Congress is sworn in on Tuesday, it will proceed to vote on filling the Speaker. With McCarthy’s ability to get 218 votes in doubt so late in the game, his bid could potentially fail in the first round, which has not happened in Congress in precisely 100 years.

The last time such an incident took place was during the swearing-in of the 68th Congress in early 1923. Frederick H. Gillett, a Republican and former governor of Massachusetts, sought the speakership but was unable to secure enough votes in the first round. In an echo of McCarthy’s current predicament, this was due to the fact the that GOP’s majority was thin, with 223 seats to 206 for Democrats.

Since the House of Representatives can not move forward onto other matters without a Speaker, it would move forward with further rounds of voting in the event that the first round failed. In Gillett’s case, it took nine rounds of voting before he was successfully elected. However, such cases have been known to take much longer to resolve.

Contested and prolonged Speaker races were much more common during the time prior to Gillett’s race, with 14 of the first 68 Congresses requiring multiple rounds of voting. While it was most common for a Speaker to be elected in less than 10 rounds of voting, the record for the most rounds was set during the 34th Congress in 1855, which took 133 rounds over the course of three months to elect Nathaniel Prentice Banks.

Newsweek reached out to McCarthy’s office for comment.