During the summer of 2018, Trump was predicting a “red wave,” a retort to predictions of a “blue wave,” though as Election Day approached, he backed off that prediction, telling the Associated Press in October that he would not accept blame if Republicans lost the House, and saying this week that he was concentrating on preserving the GOP advantage in the Senate, acknowledging the prospect of losing the House.

As the results became clear Tuesday night, Trump tweeted:

Tremendous success tonight. Thank you to all! — Donald J. Trump (@realDonaldTrump) November 7, 2018

The president also called Pelosi to congratulate her. Yet despite his effort to put a brave face on the results, it’s a bad night for Trump. While Republicans scored big victories in the Senate and in several hotly contested gubernatorial races, the Democratic House is likely to be a particular irritation to the president himself.

The Democratic victory ends a brief period of unified Republican control of government, including the White House, the House, the Senate, and effectively the Supreme Court. The House has been in Republican hands since the 2010 Tea Party wave. As The Washington Post notes, this is the third time control of the chamber has flipped in the past 12 years, a level of vacillation not seen since the immediate post–World War II period.

Republicans hand over the gavel with a decidedly mixed record. They successfully stymied much of President Barack Obama’s agenda from 2011 on, but they largely failed to further conservative priorities. Federal spending continues to grow; entitlements have not been cut; Obamacare remains in place, though scaled back; and after aiming for a tax-code overhaul, they had to settle for temporary tax cuts. Much of that class of 2010 has left the House or is leaving this year, and the party is also losing its leader. Wisconsin’s Paul Ryan, hailed as one of the GOP’s brightest young thinkers, was reluctantly thrust into the speakership, but opted to retire this year, apparently tired of being caught between the unpredictable and often outrageous president and a fractious caucus.

Read: National politics has taken over America.

It’s likely that the Democratic leader, at least initially, will be a familiar face: former Speaker Nancy Pelosi. Although a growing number of Democrats have chafed against her leadership, and some won election this year promising not to vote for her, she remains the heavy favorite to reclaim the gavel—at least to begin. Pelosi has been eager to reclaim the speakership, after serving in that role from 2007 to 2011, but has said she is likely to be a “transitional” leader, paving the way for a new Democratic speaker in the near future.

Given Republican control of the Senate and White House, Democrats will have little chance to enact their policy priorities. Where they are likely to make their biggest impact is in oversight of the White House. The majority means Democratic chairs of committees will have subpoena power, and are likely to deluge the Trump administration with requests for documents and testimony on a range of issues. They could demand to see the president’s tax returns. They could even attempt to impeach him.

For Trump, the frustration will not end there. He’s never enjoyed working with Congress, and has expressed frustration at the slow pace of both chambers. Having the opposition party in control of the House will create further gridlock. If there’s a silver lining for the president, though, it’s that a Democratic House will create a useful foil for him as he runs for reelection in 2020.