LAS VEGAS -- Marco Rubio wants you to know he was not always the pick of the dreaded Republican Party establishment.

As Florida's junior Republican U.S. senator rallied a couple hundred supporters in a hotel ballroom here the day before the fifth Republican presidential debate, he has emerged as the most likely contender for the hearts of Republican insiders who fear Donald Trump and hate Ted Cruz.

But Rubio well knows that for today's Republican primary electorate, being the establishment guy is the kiss of death. He did not go all Trump or Ben Carson and threaten to leave the party, but he did remind the crowd of his outsider credentials:

"That's why I chose to run for president. And that's why I ignored the voices in the Republican establishment in 2009 when they told me it wasn't my turn to run for the Senate. And that's why I ignored them now when they said it wasn't my turn to run for president. Because for those of us who want this nation to be greater than it's ever been, it is our turn. The time for us to act is now."

Rubio was, in fact, the tea party guy in his 2010 U.S. Senate race who forced out establishment pick Charlie Crist (who later became a Democrat). And this time, he was encouraged to wait behind his former mentor, Jeb Bush, as Bush mounted a run.

But now Rubio, the young man in a hurry, has surged ahead of Bush and is positioned as a safer general election candidate to the party honchos than Cruz or Trump.