The party is projected to win commanding majorities in the House and Senate after thrashing Republicans in key races up and down the ballot across the country. The blue tsunami will knock Washington on its head and crush the Republican congressional bulwark that both supported and shielded Trump through the first two years of his term.

The midterm result snuffs out any chance Trump had of passing partisan legislation in the second half of his presidency. And many of the interests he has been able to pursue without Congress' input — including tariffs, the Iran war and an array of Washington-area construction projects — are sure to face sudden pushback from newly empowered Democratic majorities.

The paradigm shift hardly leaves Trump helpless, however. As president at a time of executive-power expansion, Trump wields singular authorities that could stymie Democrats' efforts to pursue their own agendas.

But with his grip on the Capitol shriveling and his approval ratings scraping record lows in numerous polls, it's unclear how much support he'll be able to muster to fight the coming political battles.

Even before Election Day, analysts and pundits had contemplated a Democratic rout so decisive that it would force a reckoning for the GOP, and potentially even pose an existential threat to Trump's "Make America Great Again" movement.

Marc Short, chairman of Advancing American Freedom and onetime chief of staff to former Vice President Mike Pence, told CNBC on Tuesday afternoon that the GOP has moved away from its conservative foundations.

"We need a refresh right now," Short said in an interview. "We've lost our way."

'Mr. Veto'

Trump has been vague about what he hopes to achieve with the rest of his term. But he has shared a vision of how he might coexist with a Democratic majority, and it involves heavy use of the veto pen.

"It's one of the stronger powers that a president has," Trump said in a Fox News interview overnight. "They'll send over things that are insane, and I'll veto them."

"And after a couple of months of vetoes, they'll call and they'll say, 'How do we get this stuff done?' And we'll work together," he said, adding, "I have a lot of friends that are Democrats."

Trump has previously stated his willingness to veto reams of legislation that Democrats send across his desk. In a New York Post podcast interview released Monday, Trump said that if Republicans don't win, "I veto everything."

Pressed to detail his plans for the next two years, Trump touted his record and said, "The most important thing is to keep it going. It's going to get better and better and better, unless people come in that hate our country."

If that happens, "I guess I'll become Mr. Veto," Trump said.

The first fight

He may soon get his chance: House Democrats, poised to be led by current Minority Leader Hakeem Jeffries of New York, are planning to pass a flurry of bills as soon as they take the reins next January, CNBC has learned.

The legislative push, first reported by The New York Times, aims to show a united Democratic caucus taking quick action on the issues they were elected to solve, especially oppressively high costs on everything from gas to groceries.

In their first 100 hours after being sworn in, House Democrats plan to introduce bills reinstating the enhanced health insurance subsidies that expired under the GOP-held Congress, and reversing the Medicaid cuts Trump signed into law earlier this year.

Democrats also plan to push forward a bill that would undo Trump's sweeping tariffs and reassert Congress' role in setting import taxes. And they will again vote on legislation to end the war in Iran, or seek congressional authorization to keep it going.

But without Trump's approval, those bills may end up as little more than symbolic gestures, as Democrats will lack the two-thirds majorities in both chambers that are required to override a presidential veto without GOP help.

And there's no guarantee the bills will even make it out of Congress: Despite their landslide victories, Senate Democrats will still end up shy of the 60 votes required to bypass the chamber's filibuster rules for most legislation, giving Republicans key leverage in the minority.

Democrats also could feasibly benefit from Trump's vetoes in the long term. Forcing the president to shoot down numerous popular bills could give them fodder in the 2028 election.

'Lawyer up'

It's far from clear whether Trump believes he can find compromise with Democrats on any of their initial legislative priorities.

But any potential for a working relationship with the opposition could be poisoned early on, as Democrats in both chambers are aggressively signaling their plans to launch politically charged investigations against Trump, his political and corporate allies and even his family members.

Winning control of House committees gives Democrats the ability to issue subpoenas under the current rules.

Rep. Robert Garcia, D-Calif., who is likely to chair the House Oversight Committee in the next Congress, said his panel will target the Trump family's business dealings, corporate corruption and alleged abuses by federal immigration agencies. He also plans to return focus to the Trump administration's handling of files related to notorious sex offender Jeffrey Epstein.

As results rolled in Tuesday night, Garcia summed up his plans in a two-word statement: "Lawyer up."

It's not just Garcia. Other Democrats have already demanded records from the Trump administration on a range of issues. Rep. Jamie Raskin, D-Md., for instance, last week accused Trump of using tariff exemptions to cut "sweetheart deals" for industries whose leaders have plied Trump with gifts.

Senate Democrats have sent similar signals.

"They are going to need to plant new forests for all of the subpoenas we'll be printing," Sen. Ed Markey, D-Mass., said in an X post late Tuesday in response to a post, appearing to refer to tech executives.

The investigations are widely expected to consume much of the rest of Trump's term.

Trump has ample experience being targeted by Democrats, who impeached him twice in the House during his first presidential term.

But with his base of support appearing to erode inside and outside of Washington, Trump may have to face his political foes with a smaller arsenal than he's used to.

"I'm not expecting Republicans to revolt" against Trump following the midterm losses, AAF's Short told CNBC. "But I'm expecting some of them to quietly distance themselves."