[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/06/16/art.rubiodemint0616.cnn.jpg caption="Sen. DeMint, on the right, is backing Marco Rubio, on the left, in the upcoming Republican primary for Florida's open Senate seat in 2010."]
WASHINGTON (CNN) - Sen. Jim DeMint said Tuesday he is "convinced" Marco Rubio can defeat Charlie Crist in the GOP's Florida Senate primary and win the state's open seat next November - even if his endorsement puts him at odds with Senate Republican leaders in Washington who are backing Crist.
Rubio flew up from Florida on Tuesday morning to greet DeMint outside the Capitol rotunda and officially receive the endorsement, his first from a sitting member of the Senate. The South Carolina senator - one of the chamber's most conservative members - described the former Florida House Speaker as one of the young leaders "who will help lead our party out of the wilderness and into the arms of a waiting American public."
Rubio called DeMint a "hero" to American taxpayers and said the endorsement has given his underdog campaign a "great boost."
When Crist announced he would seek the Senate seat in May, the National Republican Senatorial Committee and other prominent party figures in Washington quickly endorsed the Florida governor's bid, much to the disappointment of conservative activists and bloggers who favor Rubio.
DeMint said he had spoken with Senate Minority Leader Mitch McConnell and NRSC chairman John Cornyn about his decision to back Rubio, and that they are "fine" with the move. He said he hopes his announcement will give other legislators breathing room to go with their consciences and back Rubio.
"I don't think there's been any effort by the leadership to intimate anyone one way or another, I certainly haven't felt, so I think you'll see some senators, and I know some House members, jumping in behind Marco," he said.
DeMint noted that Crist called him after getting word of his decision to back his opponent. The two men chatted about how the primary would be a "good healthy debate," according to DeMint, and Crist did not try to talk DeMint out of the endorsement.
Asked if he thought the early rush by GOP leaders to endorse Crist was a mistake, DeMint said the Republican Party "has to do what it feels like it needs to do." But he also contended that "primaries are good, particularly now as we're searching for the real soul of the Republican Party."
"Anyone who thinks we should not have a primary in one of our most important states is missing the point," he said.