Minnesota Senator Amy Klobuchar will abandon her candidacy for the 2020 Democratic presidential nomination.
Senator Klobuchar came in a distant sixth place in Saturday’s South Carolina primary.
Ms Klobuchar, 59, will join Joe Biden at his Dallas, Texas rally tonight to endorse the former vice-president, US media report.
The news comes on the heels of fellow moderate Pete Buttigieg suspending his campaign on Sunday.
Despite some strong debate performances and a surprise surge in the early primary voting state of New Hampshire, Ms Klobuchar failed to gain broader traction.
On the campaign trail, the Minnesota senator sold herself to moderate voters as the candidate who could win swing states back for the Democrats. However, her profile was largely eclipsed by centrist rivals Mr Biden, 77, and Mr Buttigieg, 38.
Ms Klobuchar’s withdrawal comes on the eve of the so-called Super Tuesday primaries. On Tuesday, 14 US states will cast their votes to determine the Democratic presidential nominee.
With Ms Klobuchar’s exit, five Democrats are left in the race to take on Republican President Donald Trump – Mr Biden, Bernie Sanders, Elizabeth Warren, Michael Bloomberg and Tulsi Gabbard. With the exception of Ms Gabbard, a Hawaii congresswoman, all are septuagenarians.
Seven delegates – representatives who will cast nominating votes for a candidate at the Democratic national convention in July – Ms Klobuchar had won from previous primaries are now free to vote for someone else. A candidate must win 1,990 delegates, gathered up from primary contests throughout the country, to win the nomination. Mr Sanders, the leftwing Vermont senator, currently leads the delegate count with 60 delegates, followed by Mr Biden with 54.
Announcing her candidacy in the middle of a blizzard last February, Ms Klobuchar, a former prosecutor, pitched herself as a pragmatist who could appeal to voters in America’s geographic and ideological middle.
She opposed the “Medicare for All” universal healthcare schemes touted by her leftwing rivals, Mr Sanders and Ms Warren, making the case for what she called more “practical” health care reform.
“I always tell people,” Ms Klobuchar would say on the campaign trail. “If you are tired of the nonsense and the noise in our politics, and you are tired of the extremes in our politics and you are looking for something different, then you have a home with me”.