The Republican Party is poised to commence the 119th Congress with a razor-thin majority in the House, potentially holding just a one-seat advantage as several GOP members transition to roles within the Trump administration. This precarious margin could present significant challenges for enacting the President-elect's ambitious first 100 days agenda.

Newly elected House Speaker Mike Johnson may be leading a House with the slimmest of majorities. (FOX News)

The final outcome rests on the tight race in California's 13th Congressional District, where Republican incumbent John Duarte is narrowly trailing Democrat Adam Gray. With a mere fraction of a percentage point separating the candidates, the official results, due by December 5th, will determine whether Republicans begin the year with a one- or two-seat majority. The departures of Representatives Matt Gaetz, Elise Stefanik, and Mike Waltz to other positions further complicate the situation, leaving their seats vacant until special elections are held. This means the GOP could operate with a single-seat majority for a significant portion of the first 100 days.

Rep. John Duarte faces a tough battle to retain his seat in California's 13th District. (AP Photo/J. Scott Applewhite)

Such a slim margin leaves little room for dissent within the Republican ranks, as even a single dissenting vote could effectively stall legislation. House GOP Whip Tom Emmer, however, has downplayed concerns about the tight majority, expressing confidence in the party's ability to govern and deliver on its promises alongside President Trump, regardless of the final seat count.

House Majority Whip Tom Emmer downplayed concerns about a slim majority. (Stephen Maturen/Getty Images)

Despite Emmer's optimism, the experience of the 118th Congress, marked by internal divisions and legislative gridlock, suggests that navigating a one-seat majority could prove challenging for the incoming Speaker, Mike Johnson. The potential for intra-party disagreements on key issues like government funding could once again create difficulties in advancing the Republican agenda.