Kevin McCarthy won the GOP nomination for House speaker. Getting elected may be tricky.

As the results of the final House races fall into place, it appears that Republicans will win a slim House majority. That means that unexpected things, such as a member’s death or a party defection, could jeopardize the Republicans’ ability to enact their agenda.

A small margin isn’t unprecedented. In the current Congress, Democrats have held an edge of just a couple of seats, forcing Speaker Nancy Pelosi, D-Calif., to use every bit of leverage to keep her members in line on tough votes. (Generally, she’s succeeded.)

The House has seen even slimmer divides since the dawn of the 20th century: between 1917 and 1919, and between 1931 and 1933. But historians say these precedents provide little insight into what could happen during the next two years. Partisan conflict was less intense back then, and the parties didn’t scrap and claw for every momentary political advantage.

With such narrow margins in the House, "the majority will have to be watchful of their membership and careful in their scheduling," said John C. Fortier, a senior fellow at the American Enterprise Institute, a conservative think tank.  

Deaths, retirements, and removals from office are fairly common in the House, said C. Lawrence Evans, a government professor at the College of William & Mary. "So a very tight party margin could introduce interesting and disruptive logistical glitches throughout 2023 and 2024."

Here’s an overview of what might happen, and how.

On Nov. 15, McCarthy won the Republican conference’s secret-ballot nomination for speaker, 188-31, with the non-McCarthy votes going to Rep. Andy Biggs, R-Ariz. 

Biggs’ challenge from within the party illustrates how tricky it will be for McCarthy to be elected speaker. McCarthy must secure 218 votes from the entire House during the official vote in January, so he will need to bring Biggs’ supporters to his side to win. But if McCarthy is firmly blocked by a minority of his own conference, the search will be on for a candidate who can appeal to all wings of the party.

If the new Congress ends up at 218 Republicans and 217 Democrats, that would be the narrowest possible divide, as long as there are no third-party members in the 435-seat House (and none were elected in 2022). Then, it would take only the subtraction of two sitting Republicans, such as by death or resignation, to leave Democrats with a numerical majority of 217-216. If the GOP starts with a slightly wider majority of 219-216, Republicans would need to suffer four vacancies to fall behind Democrats. And so on.

House rules are approved every two years. Under current rules, if a Republican majority loses members, Democrats could make a parliamentary maneuver called a "motion to vacate the chair." If this motion passes, the speakership becomes vacant and the House holds a new election for speaker.

A motion to vacate the chair came in 2015 during an internal Republican dispute. Then-Rep. Mark Meadows, R-N.C., introduced such a motion to pressure then-Speaker John Boehner, R-Ohio. This motion was never formally considered, but the move alienated Boehner enough that he relinquished the speakership, paving the way for another Republican, Paul Ryan of Wisconsin, to take the reins. (Meadows later became President Donald Trump’s chief of staff.)

Under current House rules, a motion to vacate the chair can be assured of a vote only if the party’s leader approves; it cannot come from a rank-and-file member of the party.

Sitting speakers today are unlikely to allow such a motion to proceed, because it would imperil their speakerships. However, a minority leader can also sign off on such a motion. That would enable a minority party with a temporary numerical edge to force a new speaker vote.

If a Republican speaker is ousted this way and a new Democratic speaker is installed, it could be months or more before Republicans have a chance at the speakership again. That’s because House vacancies must be filled by a special election, rather than by a gubernatorial appointment, as usually occurs in the Senate. 

With special elections, holding primaries and general elections would be "difficult to pull off in less than three or four months," Evans said.

Experts are more skeptical about the possibility of a surprise strike during fleeting majority absences.

"The governing party would probably try to use delaying tactics to slow down the process of voting on the motion while it tried to get its troops back to the House floor," said Matthew Green, a politics professor at the Catholic University of America. 

Even if the minority pulled it off, experts suspect the move would be reversed once the other party marshaled its members.

A new speaker would quickly set about reshaping committee ratios and chairs, which always favor the majority party. Such changes must be accomplished by passing a resolution, a vote that the newfound majority would be expected to win. 

The most urgent of these changes would be to flip the majority of the Rules Committee, which determines the process for considering controversial legislation, such as how much time is allowed for debate and which amendments will be offered.

In the lead-up to the next Congress, members of the Freedom Caucus — the most conservative group within the House Republican Conference — have expressed interest in making it easier to remove a speaker. (Meadows belonged to the Freedom Caucus when he helped oust Boehner in 2015, and Biggs heads it now.)

A small GOP majority gives the Freedom Caucus leverage. Eric Schickler, a political scientist at the University of California, Berkeley, said that ultimately, a narrow margin "gives a small group of members a lot of leverage to cause trouble for whoever is in control."

The speaker would almost certainly need the Freedom Caucus’ blessing to win the speakership, and even if the Freedom Caucus couldn’t persuade the speaker to change rule regarding speaker removal, it might be able to leverage the threat to win other concessions. 

By contrast, a Republican speaker with a larger margin in the chamber could afford to tune out complaints such as those from the Freedom Caucus.

Meanwhile, if the Republican speaker gives in to Freedom Caucus pressure, the speaker risks a backlash from the party’s more moderate members. This matters particularly because the new majority includes seven relatively moderate GOP freshmen from New York state, said Rich Cohen, the Almanac of American Politics’ chief author. 

"They will assert themselves if they believe that the conservatives are forcing the speaker to go too far in their direction," Cohen said.

Meanwhile, the minority party might woo a lawmaker from the majority party to join its caucus, either by switching parties or becoming an independent who votes with them. This could move the minority into a numerical majority.

"There are not many members who are potential party switchers these days," Evans said, "but the few that exist could be targeted with a truly massive quantity of money, attention, and pressure."