Democrats win the majority in the U.S. Senate, where 35 of 100 seats were up for renewal on Tuesday, and make a clear breakthrough with more than 51 seats.
The loss of both Republican majorities in Congress will partially limit his power to act over the next two years, until the end of his last term.
Several figures in the administration could moreover be the subject of investigations. The actions of Elon Musk, a former member of the administration heading the Department of Government Efficiency, also promise to be scrutinized.
These representatives intend in particular to investigate financial deals involving members of the Trump family or administration.
The American president finds himself facing a Congress much less aligned with his cause.
Democratic lawmakers in the House of Representatives also have parliamentary investigative power.
The upper chamber has the power to confirm nominations of cabinet members, ambassadors, or federal judges.