“This is the national stage,” Moreno said. “He would have preferred to be in the keynote spot, but in a way this is better, a higher-profile position. Along with Christie and the other speakers in the primetime spots, you’re looking at the future 2016 candidates for president. And Marco is one of them.”

Rubio’s speech isn’t a make-or-break moment, though. His 2010 win and his rhetorical ability to advance conservative causes catapulted him into the ranks of elite conservatives in Washington.

He’s so sought-after that he conducted nine interviews in 97 minutes Monday, from local television stations to Black Entertainment Television, CNN, CNN Español, Telemundo, Univision and Fox. On Wednesday, more than a dozen cameras and more than two dozen reporters surrounded Rubio after a walk-through on the convention floor. Rubio seamlessly alternated between Spanish- and English-language interviews. As he finished, only a fraction of the reporters paid attention to former Minnesota Gov. Tim Pawlenty, who followed Rubio.

Romney’s campaign won’t say why Rubio was passed over in favor of Paul Ryan.

Republican advisers say Rubio’s record of accomplishments is thin, and the campaign would have faced uncomfortable questions over Rubio’s use of a Republican Party of Florida credit card during his time in the Legislature.

Rubio has also stuck by Rep. David Rivera, of Miami, who faces federal investigations into his campaign and private finances.

In some ways, Rubio will give his speech despite some in the Romney campaign. Anonymous consultants have secretly tried to sandbag the senator behind the scenes.

Last month, as Rubio began a tour to plug his new autobiography, An American Son, Romney advisers leaked word that Rubio wasn’t on the vice-presidential shortlist. Conservatives revolted.

Then, last week, Romney advisers tried to bump Rubio from his prime-time slot introducing Romney. Conservatives revolted again.

Not only is Rubio one of the most popular Republicans in conservative circles, he’s the party’s most recognizable Hispanic face. Leaders like former Florida Sen. Mel Martinez and former Gov. Jeb Bush have expressed concern over the Republican outreach to Hispanic voters, one of the fastest-growing demographic groups.

Bush said the party needs to “stop acting stupid” when it comes to immigration. He has also been a leading voice backing Rubio. Republican pollster Whit Ayres gushed that: "Marco Rubio is the Michael Jordan of American politics. He is enormously talented."

As the child of working-class immigrants, Rubio will likely reprise his biography. It not only tells his story to the nation; it reinforces the Republican effort to appeal to middle-class and blue-collar voters amid Democratic criticisms of the multi-millionaire who heads the ticket and won’t disclose multiple years of his tax returns.

Rubio is sure to tell the anecdote of “the man behind the bar,” his father, who would frequently serve people at banquets like the tony fundraisers his son now headlines. It’s that well-told “journey” of his family — from standing behind the bar to standing behind the podium — that Republicans hope will connect with a broader audience.

Democrats, meanwhile, expressed a measure of concern about Rubio, who had the potential to attract more Hispanic votes had he been on the ticket.

Robert Gibbs, an adviser to President Obama’s campaign, said both Ryan and Rubio had “pluses and minuses.”

But he indicated Ryan was a better candidate for Democrats to run against because the congressman drafted the much-vilified “Ryan budget” that deeply cut healthcare and college-loan programs to help pay for tax cuts.

“It’s not the Rubio budget,” Gibbs said. “It’s the Ryan budget.”

One well-known liberal, Comedy Central comedian Jon Stewart sat down with Rubio on Tuesday during an extended Daily Show episode and said it was better that Rubio didn’t get picked by Romney.

“I think this is much better for you,” Stewart said, asking how Rubio found out he wouldn’t be picked as Romney’s running mate.

“He called and let me know he was making the announcement the next day,” Rubio said.

“I cursed at him,” Rubio joked.

“You are introducing him,” Stewart said. “Have they said to you, hey, charisma boy, dude, take it down a notch?”

“All they’ve asked me to do is introduce the governor,” said Rubio. “They’ve given me 15 minutes to say anything I want.”

Rubio’s fame is certain to last longer than 15 minutes.