Democrat Doug Jones has won the special election to fill a vacant U.S. Senate seat representing the southern state of Alabama.
After a contentious campaign, voters backed Jones over Republican Roy Moore.
The result means that in January when Jones is sworn in, the Republican majority in the Senate will shrink to 51-49 and make it tougher for President Donald Trump to enact his agenda.
Senate terms last six years, but Jones will be filling out the final three years of a term begun by Jeff Sessions before he resigned in order to become attorney general under Trump.
Jones is the first Democrat from Alabama to win a Senate seat since 1992.
Moore had the backing of Trump, but faced opposition from other Republican leaders. He has been accused of sexual misconduct in the 1970s when his female accusers were teenagers and he was in his 30s.
Moore has consistently denied the allegations calling them disgusting. But he initially admitted dating young women, when he was an attorney general, before denying ever knowing any of his accusers. At least one of the women outright called Moore a liar.
