Amy Klobuchar has dropped out of the race to become the Democrat's presidential candidate and will throw her support behind Joe Biden.
The Minnesota senator is flying to Dallas and plans to join Mr Biden at a rally he is holding tonight.
It comes after Pete Buttigieg also dropped out of the race. He is also expected to back former president Mr Biden.
Both departures pre-empt Super Tuesday, a pivotal moment in the Democratic race.
Ms Klobchar had outlasted several better-known and better-funded Democrats, thanks to a better-than-expected third-place finish in in New Hampshire.
However, but she could not turn that into success elsewhere as she struggled to build a campaign that could compete across the country. She had poor showings in the next contests.
She was hoping to own the moderate lane of a Democratic field that grew to two dozen candidates. However, that got tougher when Mr Biden joined the race in April.
On Tuesday, 14 states, one US territory and Democrats abroad cast ballots in the party’s nomination fight.
Ms Klobuchar and Mr Buttigieg become the second and third Democrats to abandon their presidential bids since Mr Biden scored a resounding victory in South Carolina.
A shrinking group of other Democrats vowed to press on, potentially towards a contested convention.
Bernie Sanders remains the undisputed front-runner, but the rest of the field is unsettled, even after Mr Biden’s South Carolina win and the departures of Mr Klobuchar, Mr Buttigieg and billionaire activist Tom Steyer.
