REUTERS/Aaron P. Bernstein
Marco Rubio.
On Monday, Rubio's campaign sent out at least seven emails detailing new endorsements the candidate has picked up following Bush's exit after Saturday's South Carolina primary.
Those endorsements included several congressmen, Sens. Thom Tillis and Jeff Flake, and Tim Pawlenty, the former Minnesota governor who ran for president in 2012.
One of the biggest endorsements came on Monday afternoon, when Bob Dole also threw his support behind Rubio. Dole is a former Senate majority leader and won the Republican Party's presidential nomination in 1996.
"He worked for my '96 campaign in Dade County, Florida, and so I've had an acquaintance with him way back in '96 when he was a hard worker," Dole, who was a Bush supporter, told ABC's Jonathan Karl.
Dole also praised John Kasich, another candidate, but criticized Ted Cruz, a 2016 contender whom Dole has repeatedly attacked.
"He wants to grow the party as opposed to Cruz," Dole said of Rubio.
Not long after Dole's endorsement emerged, news broke that Orrin Hatch, the longtime Utah senator and president pro tempore of the Senate, also endorsed Rubio. He was also a former supporter of Bush's White House bid:
NEWS: Orrin Hatch says to us he will endorse Rubio. He had backed Jeb. More evidence of establishment rallying behind Marco.
The recent flock of endorsements adds to an already impressive collection by Rubio. In South Carolina, he picked up the endorsement of Gov. Nikki Haley, Sen. Tim Scott, and Rep. Trey Gowdy. He was also endorsed by former Louisiana Gov. Bobby Jindal, former New York Gov. George Pataki, and former Pennsylvania Sen. Rick Santorum, all of whom were candidates for president earlier in the campaign.
There were even reports that Mitt Romney, the 2012 Republican nominee and a former Massachusetts governor, would be endorsing Rubio, but Rubio's campaign dismissed the reports as unfounded.
Rubio has yet to win a primary or caucus, but he is coming off a strong showing in South Carolina, where he finished second to Donald Trump.
Bush was considered the early favorite for the Republican nomination and gained plenty of establishment support and money for his bid. He was at the top of the polls before Trump labeled him as a "low-energy" guy last summer.