With the midterm election over and the House set to fall back under Democratic control, Capitol Hill is already reorganizing itself in anticipation of a hellacious new reality. “Tomorrow will be a new day in America,” Nancy Pelosi declared on Tuesday night, shortly after Fox News, CNN, and other political scorekeepers made the call. “Today is about more than Democrats and Republicans,” she continued. “It is about restoring the Constitution’s checks and balances to the Trump administration.” The threat was not lost on Trump. “If the Democrats think they are going to waste taxpayer money investigating us at the House level, then we will likewise be forced to consider investigating them for all of the leaks of classified information, and much else, at the Senate level,” the president shot back on Twitter. “Two can play that game!”

Trump may sound defiant—may even welcome the chance to make Pelosi his foil for 2020—but inside the White House, advisers are justifiably depressed by the prospect of two (or more) years under the microscope of the House Oversight Committee. The Trump administration, after all, has produced scandals at an alarming rate, from a campaign that remains under investigation by the Justice Department to corruption investigations into a half-dozen Cabinet officials, to the firing of Jeff Sessions. Most controversies have been swept under the rug by Republican lawmakers who dutifully looked the other way. Now, Democrats are ready to make Trump’s life hell. “Congress is going to force transparency on this president,” one Democratic congressional aide told me. “Once there is transparency, I am sure there are going to be a lot of questions that flow from that.”

Wielding the power to subpoena documents, administration officials, and Trump associates, House Democrats can pursue any and all lines of inquiry their Republican colleagues ignored. And there will be little Trump can do to stop them. “It seems that the prospect of oversight and investigations has already gotten very much into the president’s head, since it was very much a focus of his election commentary,” Bob Bauer, who served as White House counsel to Barack Obama, told me. “The White House can be affected by these matters in a range of ways, including the way it staffs up, allocates resources, and sets legislative strategy, but the impact is magnified if the executive is obsessed with his perception of the threat, as he may already be.”

Impeachment—a liberal wet dream and Democratic Party nightmare—is on the back-burner for now, at least until Robert Mueller returns with his Russia report. Pelosi, who has been in Congress long enough to remember how the Clinton impeachment trials backfired for Republicans, said Tuesday that such a drastic move would “have to be bipartisan,” and that “the evidence would have to be so conclusive.” Congressman Jerrold Nadler, who is set to take over as chairman of the House Judiciary Committee, and would take the lead on initiating impeachment proceedings, released a statement promising “accountability” and “oversight,” but not much else. (On Wednesday afternoon, after Sessions was fired, he vowed to use his power to protect Mueller’s office from political interference.)

But there is much that is likely to happen in the meantime. California Congressman Devin Nunes, the bumbling, sycophantic chair of the House Intelligence Committee, will pass the gavel to ranking Democrat Adam Schiff, also of California, who has promised to deploy the full resources of the committee to get to the bottom of the Russia affair. He has also been forthright in his contempt for Nunes, who he accused on Tuesday of having run interference for the administration. “The majority went further by being complicit in the president’s attacks on the independence of the Justice Department, on the men and women of the F.B.I., on our intelligence community,” he said, after handily winning re-election in his district. “So we also need to restore the relationship between our committee and the intelligence community and law enforcement.”