Republicans in the U.S. House of Representatives will hold a slim 220-215 majority when the next Congress gets underway next month after Democrats picked up a seat in California, according to Edison Research on Wednesday.

With House Republicans likely to hold just 220 or 221 seats during the upcoming session of Congress, they will have little room to manuever

The final race to be called in the 2024 House of Representatives elections has been called for a Democratic candidate, meaning Republicans’ margin of control in that chamber of Congress will be among the most narrow in U.S. history.

The Republican speaker held on to control of the House, but will preside over an even smaller majority at a time when President-elect Donald J. Trump will need his help to achieve major agenda items.

Pennsylvania’s state House map makes districts politically representative, but less competitive. This makes it hard for either party to get a big majority.

A California Democrat eked out a win in the final outstanding House election race, setting up an even narrower Republican edge in the coming Congress and signaling potential headaches for the ruling GOP.

The narrow majority leaves Republicans with even less margin for error as they try to enact President-elect Trump’s agenda.

Republican Rep. John Duarte has conceded to his Democratic challenger Adam Gray in California’s 13th Congressional District, Duarte campaign spokesman Duane Dichiara confirmed to CNN.

Republicans will have a narrow majority in the House, with Democrats flipping one final seat in California, leaving GOP leaders with even less margin for error.