Responding to President Obama's charge that Mitt Romney has adopted extreme positions, Sen. Marco Rubio (R-Fla.) said Sunday that the president is leveling his attack because he lacks the record to run for reelection by pointing to improvements in the state of the country.

(Lynne Sladky - AP)

"Barack Obama can't run by saying, 'Vote for me because things have gotten better.  Vote for me because my ideas have worked.' And so I think you're going to see more and more of this type of rhetoric on his behalf," Rubio said on CBS' "Face The Nation."

In interview with AP, Obama said Romney "has signed up for positions, extreme positions, that are very consistent with positions that a number of House Republicans have taken."

Rubio defended the presumptive GOP nominee saying, "what I think Mitt Romney understands and Barack Obama does not, is the creation of new businesses and the starting of new businesses.  That doesn't happen because of tax increases or some government program.  That starts because somebody has the confidence and the money to invest in the American economy."

Rubio is slated to introduce Rommey at this week's Republican National Convention in Tampa. He said the Romney campaign has not sought to micromanage his remarks.

"They -- actually have not asked me to say anything in particular other than understanding I'm going before Governor Romney," Rubio said. "The -- you know, usually I don't even write speeches. I have general thoughts, but this one of course is a big one so I will. I write these myself, for the most part, with some help in terms of just getting it framed right.  But I usually want my own words to come through. And-- I look forward to doing that."