WASHINGTON -- Republicans have secured their monopoly on power in Donald Trump’s new Washington, retaining their majority in the House of Representatives, CNN projected Wednesday, after picking up seats in California and Arizona and ushering in a dramatic new era of right-wing populist rule.

The GOP’s control of both chambers of Congress means that the U.S. president-elect will have a path to enact an agenda that could profoundly change America, including sweeping tax cuts, hardline immigration enforcement and a transformation of domestic and foreign policy.

Republican dominance of Capitol Hill is just one aspect of Trump’s formidable new power base. A president-elect who already believed that he had all-but-limitless power will be emboldened by last summer’s Supreme Court ruling offering substantial immunity to the commander in chief for official acts taken in office.

Trump may also have the chance in the next four years to replace older members of the court, potentially extending until the middle of the century the conservative majority he built in his first term.

And as Trump unveils his team of Cabinet members and top West Wing staff, made up largely of ultra loyalists, it’s already clear that the 47th president will face few of the restraints that experienced career officials tried to impose on some of his most outlandish schemes when he was the 45th president.

Trump’s team is promising an aggressive first 100-day agenda to enact as much of his “Make America Great Again” plan early next year after tapping into the public’s concern about high prices and undocumented migrants to help the GOP win the White House, the Senate and now the House.

Republicans flipped the Senate by defeating Democrats defending red states and, with one outstanding race yet to be projected, they control 52 seats. While the Senate filibuster means that 60 votes are needed to pass most major legislation, party leaders will be able to use the same budgetary devices that helped President Joe Biden pass some big-ticket items.

The GOP’s victory in the House represents a triumph for Speaker Mike Johnson, who struggled to control his restive conference over the last year. The House GOP often plunged into chaos and infighting — some of which was exacerbated by Trump’s interventions and the behavior of some of his most outspoken supporters. The narrow majority meant that any one member could decide to stage a revolt or to break with leadership for personal political gain.

The question now will be how large next year’s House majority becomes and whether the GOP can widen the margin of a handful of seats that has made managing the conference so complex for Johnson. The fact that Trump will be in the White House with the GOP in full control could make unity easier next year. However, Trump is already poaching from the incoming majority for his Cabinet picks, and even with those members hailing from safe Republican seats, their likely vacancies could last long enough to cause headaches for Johnson.

Democrats had held out fading hopes in the days after the election that they could flip the House and create a sole bastion against Trump’s rule — a feat that looked like a possibility for much of the year given the chamber’s unproductive record and Johnson’s struggle to assert control. Democrats were targeting Republicans sitting in districts that Biden had won four years ago – many of which were in New York and California – but with Trump’s resounding victory this year, some of those seats became harder to pick off.

Democrats are now left with the momentous task of regrouping ahead of the midterm elections in 2026 — without a single platform of power in Washington.

Republicans had seized back the House in the 2022 midterm elections to put a brake on Biden’s term, largely through winning a flurry of those competitive seats in New York and California. Democrats managed to flip several New York seats this year, but Trump’s relative strength for a Republican presidential candidate in the state of his birth helped limit Democratic gains. Democrats also failed to knock off some other key targets, like GOP Rep. Don Bacon, whose Omaha-area district in Nebraska gave Vice President Kamala Harris an electoral vote. And the GOP captured some of its top targets in Pennsylvania and Michigan.

That left the destiny of the House playing out in counts stretching well past Election Day in California, Oregon, Arizona, Iowa and Alaska, among other places.

Democrats held on to some of their most competitive seats, however, like that of vulnerable Washington state Rep. Marie Gluesenkamp Perez, and were hopeful about others in Ohio and Maine in strong Trump territory.

Johnson, who rose from obscurity on the backbenches to the speakership after a party meltdown following the ouster of previous House Speaker Kevin McCarthy in 2023, anchored his strategy to keep the chamber — and, if possible, enlarge his majority — on a tight alliance with Trump. The Louisiana Republican travelled to the president-elect’s Mar-a-Lago resort to celebrate on election night and his office has been coordinating closely with the transition team.

And on Wednesday, before Trump’s arrival at a closed-door meeting with House Republicans, Johnson heralded the president-elect as “the comeback king,” according to a source in the room.

Trump backed his bid to remain speaker, and the Louisiana Republican was later nominated unanimously by voice vote, two sources in the room told CNN. He’ll face a House floor vote on January 3.

Despite some conservatives pressing Johnson – on everything from not sending more money to Ukraine to why the GOP didn’t win more seats – the party largely projected unity behind Trump and his backing of Johnson.

“If Donald Trump says jump three feet high and scratch your head, we all jump three feet high and scratch our heads,” GOP Rep. Troy Nehls of Texas told CNN. “That’s it.”

The speaker does face one looming crisis — a need to raise the government’s borrowing limit, perhaps by early summer, although there may be limited appetite from fiscal hawks in the party to provoke a showdown that could anger Trump.

CNN’s Annie Grayer, Haley Talbot and Aileen Graef contributed to this report.