• The race to control the House is undecided, though Republicans are already optimistic about securing a governing trifecta with their new Senate majority and President-elect Donald Trump.
• Republicans need to win 12 more seats to maintain their majority, while Democrats need 33 more to flip control.
• The prevailing party will ultimately dictate the boundaries of power of the next Trump administration.

The race to control the House is undecided, though Republicans are already expressing early optimism about securing a governing trifecta with their new Senate majority and freshly minted President-elect Donald Trump.

"As more results come in it is clear that, as we have predicted all along, Republicans are poised to have unified government in the White House, Senate and House," Republican House Speaker Mike Johnson said Wednesday in a statement.

That early confidence comes as Republicans need to win 12 more seats to maintain their majority, while Democrats need 33 more to flip control.

According to NBC News' race tracker, 20 key House districts remain uncalled. The others are so far unlikely to be flipped.

Among the remaining races are California's 47th Congressional District, Maine's 2nd and Alaska's at-large district, where Republicans are looking to pick up seats, along with California's 45th, one of the most expensive races in the country.

"The path to take back the majority now runs through too close to call pick-up opportunities," House Minority Leader Hakeem Jeffries, D-N.Y., said in a Wednesday statement. "The party that will hold the majority in the House of Representatives in January 2025 has yet to be determined. We must count every vote."

House GOP members entered the 2024 contest with a historically slim majority — 220 GOP seats to Democrats' 212 with three vacancies.

Democrats poured huge sums of money into House races, trying to flip the lower chamber. They far outspent their Republican rivals in many of the most competitive House races across the country.

House Democratic candidates in races rated either "toss-up" or "leaning" by the Cook Political Report with Amy Walter spent $132 million versus Republicans' $61.6 million, according to October filings with the Federal Election Commission.

The prevailing party will ultimately dictate the boundaries of power of the next Trump administration. A fully Republican-controlled House would likely provide the president-elect a loose legislative leash, while a Democratic House would likely tighten it.

If Republicans win, it would also mean Johnson will have the chance to extend his tenure. If not, it would likely mean a promotion for current House Minority Leader Hakeem Jeffries of New York, the favorite to become speaker in a Democratic victory.

Over the next two years, the House will face key battles on government funding, tax levels, immigration and corporate regulation.

In September, Congress passed a temporary funding bill to avert a government shutdown, which will expire Dec. 20, teeing up another budget battle just before the next president takes office in January. The prospect of divided government could further complicate that fight.

Also on the next Congress' plate is the potential extension of the 2017 Tax Cuts & Jobs Act, which is due to sunset in 2025. Trump wants to make that law permanent and deepen some of the tax cuts.