By JoAnne Allen
WASHINGTON (Reuters) - Florida Senator Marco Rubio, a favorite of the conservative Tea Party movement, endorsed Mitt Romney on Wednesday calling the former Massachusetts governor the inevitable Republican presidential nominee.
"I am endorsing Mitt Romney and the reason why is not only is he going to be the Republican nominee, but he offers at this point such a stark contrast to the president's record," Rubio said in an interview on Fox News.
In the state-by-state race for the right to face Democratic President Barack Obama in the November 6 election, Romney leads with an estimated 565 delegates, according to Real Clear Politics.
Former Pennsylvania senator Rick Santorum is next with 256, delegates, followed by former House Speaker Newt Gingrich with 141 and Texas Congressman Ron Paul with 66.
Former President George H.W. Bush will formally endorse Romney on Thursday at an event in Houston. A long list of establishment Republicans have endorsed his presidential bid, including former Florida governor Jeb Bush and 2008 Republican presidential nominee John McCain.
In announcing his support for Romney, Rubio said the White House hopeful's experience in the private sector "offers a very clear alternative" to the direction Obama is taking the country.
Rubio was critical of the strategies of Santorum and Gingrich to pursue the Republican nomination in a floor fight at the party's nominating convention in Tampa, Florida, in August.
"I think that's a recipe to deliver four more years to Barack Obama," Rubio said.
A first-term senator and rising Republican star, Rubio has often been cited as a potential vice presidential candidate for the Republican nominee. On NBC's "The Tonight Show with Jay Leno" on Tuesday, Romney said the Florida senator - the son of Cuban immigrants - represents "the American dream."
Rubio again shot down speculation that he might accept the second spot on the Republican ticket.
"I don't believe I'm going to be asked to be the vice presidential nominee," Rubio said. "That's not what I intend to be. That's not what I want to be and that's not going to happen."
(Additional reporting by Steve Holland; editing by Todd Easthm)