Marco Rubio’s former chief of staff Richard Corcoran endorsed rival Jeb Bush on Monday, the latest in the brewing feud between the two Republican candidates from Florida.
Corcoran was Rubio’s chief of staff when Rubio was the House speaker in Florida’s House of Representatives, a position Corcoran was recently selected to hold from 2016 to 2018.
"I have known Jeb Bush for over 20 years. As Governor, Jeb Bush set the standard against which all other conservatives in this state are measured — no one in Florida would argue that. Jeb Bush always stepped up and was true to his principles, even if that meant facing difficult consequences,” Corcoran said in a statement provided by the Bush campaign to NBC News. "I saw him in moments when it would have been easy to cave to the special interests and just go along with the status quo; yet he never did. He is without question, the most courageous, conservative in this race. That’s what I want in a leader, and what I know the electorate deserves. When the people of this country get to know the Jeb Bush that I know, they will have no doubt that he is the right choice to become the next President of the United States."
RELATED: Trump revels in Rubio-Bush feud
Corcoran will join Bush on campaign stops in Florida on Monday, just days after simmering tension between the Florida senator and former Florida governor came to a boil at the third GOP presidential debate, with Bush calling out his one-time mentee for his Senate attendance record — only to have Rubio counter-punch back effectively, creating a cringe-worthy moment.
“The only reason you’re doing it now is because we’re running for the same position. Someone convinced you attacking me is going to help you,” Rubio fired back.
The once close conservatives have turned on each other to try and distill their own platforms, with Bush arguing that he's the seasoned reformer with a record to back him up and Rubio arguing that he's the change-focused upstart unwilling to respect the political structures that have failed the nation. Both Rubio and Bush were largely thought to be strong candidates for the general election, but they've been so-far overshadowed by political outsiders Ben Carson and Donald Trump.
Hours later, Rubio announced a big endorsement of his own: His first endorsement from the Senate, Colorado Republican Cory Gardner.
"I believe Marco Rubio presents us with an opportunity Americans can be excited about — and that's the generational opportunity, generational choice for all Americans," Gardner said Monday on Fox News.
Gardner, a rising young star within the party, represents the deeply purple Colorado, where one-in-five are Latino and nearly half are registered to vote.
Gardner pitched Rubio as the most electable candidate in the general election.
"If we are going to put Marco Rubio on the ballot, that's our best foot forward,” he said, “our best opportunity to defeat Hillary Clinton."