Moderate Democrats rallied around former Vice President Joe Biden ahead of several major primaries across the U.S. on Super Tuesday (March 3).
Former candidates Pete Buttigieg and Amy Klobuchar, endorsed their old rival on Monday night (March 2).
Both contenders had only recently dropped out of the race.
The last-minute endorsements are a rallying cry for moderate Democrats ahead of Super Tuesday.
They fear that current frontrunner Bernie Sanders, a self-described democratic socialist, cannot win against Republican President Donald Trump.
Fourteen states will be voting, with a total of over 1,300 delegates up for grabs.
The sum is the largest one-day haul of the approximate 2,000 delegates needed to win the Democratic nomination.
The races will be crucial for Biden.
His campaign faced early losses in Iowa and New Hampshire, only recently bouncing back with a resounding victory in the South Carolina primary.
Biden will also be competing with Mike Bloomberg for moderate Democrats' votes.
Bloomberg will be making his debut on Super Tuesday, having poured $500 million into his campaign to make up for missing all the earlier primaries.
Only five candidates, including Biden, Bloomberg and Sanders, remain in the Democratic race, down from more than 20 earlier in the campaign.