Republicans predicted they’d win the bulk within the Home of Representatives, thereby securing the Republican trifecta

House Speaker Mike Johnson, R-La., holds the gavel on stage before the start of the first day of the Republican National Convention at the Fiserv Forum in Milwaukee, Wisconsin, July 15, 2024.

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Republicans will retain control of the House of Representatives, NBC News predicted Wednesday.

The forecast comes a week after President-elect Donald Trump, a Republican, won a decisive victory in the presidential election against Vice President Kamala Harris and the GOP won majority control of the Senate.

Before the election, Republicans wanted to expand their razor-thin majority in the House of Representatives. They governed with 220 Republican seats to 212 Democratic seats and three vacant seats.

That slim GOP majority gave Democrats high hopes of flipping the chamber. They only needed to gain four net seats to regain control, as the vacant seats left the chamber with fewer than 435 total votes.

According to an NBC News analysis of October campaign finance data, Democrats outperformed their Republican rivals in all but one of the 26 House races, which the Cook Political Report with Amy Walter rated a “switch.” Democrats also outperformed Republicans in the crucial elections from July to September.

Despite massive fundraising efforts, Democrats failed to win the 218 seats needed to gain control of the House of Representatives.

In Pennsylvania's 8th Congressional District, Republican Rob Bresnahan defeated incumbent Democratic Rep. Matt Cartwright, and in the state's 7th District, Republican Ryan Mackenzie defeated incumbent Democratic Rep. Susan Wild, two particularly hotly contested races.

In the battleground state of Michigan, Republican Tom Barret secured a vacant seat in the 7th Congressional District previously held by Democrat Elissa Slotkin, who declared victory in her race for Michigan Senate.

The single-party controlled Congress will have a host of key issues to address, including whether to extend the $3.3 trillion Tax Cuts and Jobs Act, much of which expires next year. Trump signed the first bill in 2017, saying he not only wanted to extend the tax breaks but also seek deeper cuts.

Congress also has the prospect of extending expanded subsidies under former President Barack Obama's Affordable Care Act, which expire at the end of 2025. There is also a fight over the debt ceiling.