TAMPA -- Marco Rubio introduced the leader of his party to the nation Thursday night, but judging by the roar of the crowd, some initially wished it was the other way around at the Republican National Convention.

The freshman Florida senator had just 15 minutes as the warm-up act for Mitt Romney, and Rubio made the most of them.

Speaking occasionally in Spanish, Rubio’s address served three purposes: It branded him as a national Hispanic leader in the Republican Party. It played up the best parts of Romney’s biography. And it kept the focus on President Barack Obama.

“Our problem with President Obama isn’t that he’s a bad person,” Rubio said. “By all accounts, he, too, is a good husband, and a good father … and thanks to lots of practice, a pretty good golfer.”

The crowd laughed.

The killshot followed the punch line.

“Our problem is that he’s a bad president,” Rubio said.

The crowd roared.

Short on policy specifics, Rubio’s speech was long on biography, rhetorical flourishes, references to God and paeans to the dreams of America that helped put the convention crowd in a swoon. A few grew misty-eyed, especially Cuban Americans moved by his opening line to remember the tyranny in Cuba.

Some murmured that Rubio or Romney’s running mate, Congressman Paul Ryan, should headline the ticket — a refrain heard frequently in Republican circles during the primary.

But Romney’s speech — crisp, clear and sometimes emotional — put an end to that talk at the Tampa Bay Times Forum.

Rubio’s speech made clear that he’s unequivocally behind Romney, who almost chose him as a running mate. The address came at the close of three days of re-branding by a Republican Party and a presidential ticket that has taken a beating from Democrats over Romney’s likability.

Rubio’s mere presence in primetime was a rebuttal to Democratic charges that the GOP’s policies — chiefly over immigration — are bad for Hispanics, who overwhelmingly back Obama, polls show.

Rubio never mentioned immigration.

Instead, he spoke of the immigrant experience, of how he’d sit and listen to his Cuban grandfather puffing on Padron cigars and holding forth on history, politics and baseball.

“I don’t recall everything we talked about, but the one thing I remember, is the one thing he wanted me to never forget. The dreams he had when he was young became impossible to achieve,” Rubio said.

Rubio said his father, a bartender, worked 16-hour days and that his mother, a maid and K-Mart stock clerk, often worked overnight shifts.

“My Dad used to tell us: ‘ En este pais, ustedes van a poder lograr todas las cosas que nosotros no pudimos,’ ‘In this country, you will be able to accomplish all the things we never could,’ ” Rubio said.

Rubio compared his family’s struggles with those of Romney’s family, which had briefly fled to Mexico.

“His family came to America to escape revolution. They struggled through poverty and the Great Depression. And yet he rose to be an admired businessman, and public servant,” Rubio said.

“And in November, his son, Mitt Romney, will be elected President of the United States,” Rubio said.

The attempt to re-fashion Romney as the heir to immigrants and the scion of a family with once-humble roots comes after months of withering assaults from Democrats on Romney’s business background.