Marco Rubio isn't the frontrunner to be the Republican presidential nominee in 2016. That's either Jeb Bush or Scott Walker.

But, Rubio, who will announce his presidential campaign later this afternoon in Miami, is the single most naturally-talented candidate in the race.  And natural ability -- as we've seen with people like Bill Clinton and Barack Obama on the Democratic side -- can go a very long way in a presidential race.

The speech above tells you everything you need to know about just how high Rubio's ceiling could be.  It's his keynote address from the 2012 Republican National Convention, the biggest speech of his life until tonight.

And, Rubio absolutely slays it -- delivering a touching re-telling of his own biography as symbolic of the broader exceptionalism of America. (Adding to Rubio's degree of difficulty that night was the fact that he was directly preceded on stage by the absolutely bonkers speech of actor Clint Eastwood.)  I dare you to watch/listen the speech and not feel something stir in your gut when Rubio tells how his father worked as a bartender in the back of rooms so that one day his son could stand in the front of the room. (It's around the 13:30 mark.)

"Yes we live in a troubled time, Rubio says in one of the most powerful lines of that speech. "But America has always been about new beginnings."

We knew the Florida senator was talented. But his speech on Thursday night showed that he is a MAJOR political star. Rubio's speech was, without question, the best of the convention. He seemed entirely at ease in the massive national spotlight -- compellingly telling his life story and mixing in jabs at Obama in a more-in-sorrow-than-anger tone that made the hits more powerful. (One example: "Our problem is not that he's a bad person. Our problem is that he's a bad president.")  It's uniquely possible that we will look back in four or eight years to this night as the time when it became clear Rubio had that something special that made him a force to be reckoned with in presidential politics.

Rubio's ability to deliver a speech like the one he gave at the GOP convention when coupled with his profile as the youngest candidate in the race and a Cuban-American makes him dangerous (in a good way) as a candidate.

Now, giving a single speech -- or even a series of good speeches -- does not mean that you win the nomination or the presidency. (And, as Rubio's detractors note, he did choke, almost literally, during his 2013 Republican response to the State of the Union.) But, in a presidential race, raw talent can be a remarkable leveler. And Rubio absolutely has that.