"If you look at the last 10 days," Rubio says of the polls, "those numbers have begun to narrow down again, and we're basically, I think, back to where we already were before the conventions. . . .
"I'm very optimistic that our proposition is still a 50-50 one, maybe a little bit better."
And from that dead heat, the campaign enters a new phase.
"People are going to, for the first time, be able to size up Mitt Romney standing next to Barack Obama," Rubio says. "No media filter, no columnists, no commentators telling them what so-and-so said."
There, Romney can make his case that Obama's policies are impeding recovery.
"In addition to the things that have happened over the last five to six years," Rubio says, "the president has decided to embrace big government as a solution to our economic problems.
"That's a solution that hasn't worked anywhere in the world and isn't going to work now. And in the real world, where people are making decisions on where to put their money, where to start a business, that kind of policy discourages them from doing it."
Rubio says that Romney "offers a fundamentally different way . . . one in which the government's job is to create the conditions for the private sector to grow. . . .
"The only way out is a combination of fiscal discipline in the future and economic growth, explosive economic growth," Rubio says, but that can only happen "when people have confidence . . . that the government is going to regulate them and tax them in an affordable way."
That won't happen under Obama.
"I can only judge him on what he's done the last four years, and he's never really been interested in solutions, especially the last two years," Rubio says. "He has not offered any way to solve Medicare. He talks about tax reform, but has never offered a tax-reform plan. He talks about modernizing immigration, but he's never offered an immigration reform plan.
"The only big things he's ever offered are the stimulus, which was government spending - it didn't take a lot of creativity - and Obamacare, which is an unmitigated disaster for America economically. He's offered nothing else in terms of big ideas."
With one of the debates focused on foreign policy, there will also be a chance to show that it was Obama, not Romney, whose credibility has been damaged by recent events in the Mideast.
While the media were busy attacking Romney, the State Department seemed clueless about what happened in Libya in a briefing with senators, Rubio says. Worse, he notes, are reports that Chris Stevens, the slain U.S. ambassador, had expressed concerns about his safety.
"But I think the most outrageous thing of all is that, for a whole week, [the administration] sent the message that this is all - what happened in Benghazi - completely the result of a YouTube video. . . . Why didn't they just come out and say this was an act of terrorism?"
Romney will do better, Rubio believes, because he understands the threats that America faces, and he has the right "fundamental principles" on foreign policy.
"Mitt Romney is not under any delusion that somehow radical Islamists hate America because George Bush wasn't nice to them," Rubio says. "He fundamentally understands that radical Islam hates America because radical Islam wants the whole world to be Islam. . . . If you don't agree with it, they think they have the right to kill you or subjugate you. . . .
"The president thought that if he just did more outreach to them, then they would change their behavior. . . . He could give a speech in Cairo and everybody in the region would decide, 'Oh, he's different than George Bush, we can deal with this man.'
"I think the message needs to be that I believe the vast majority of people in the Muslim world do not want radical Islam to be their future and we'll support them. But those who are radical Islamists, who want to bring the whole world under their control, either they win or we win. We have to send a very clear message that their behavior will only bring problems for them.
"I think Mitt Romney's principles are solid on that, and the president has not been, and that's why we're paying a terrible price for it now."
Let the debates begin.
Listen at www.philly.com/rubio , choosing the Dom Giordano show from the index on the left.
Contact Currents editor Kevin Ferris at email@example.com or 215-854-5305.