Despite having run a rocky campaign while struggling in the polls, Bush is the only establishment candidate who has built a national organization that rivals Rubio’s. It’s Bush’s high-spending super PAC, Right to Rise, which has pummeled Rubio across the airwaves with tens of millions of dollars in attacks — and officials say it will continue to do so long as the former Florida governor stays in the race.

And if Bush continues his campaign beyond the Super Tuesday primary on March 1, as his confidantes promise he will, he could make it harder for Rubio to win what will be one of the biggest prizes in mid-March: Their home state of Florida, which awards all of its delegates to the winner rather than handing them out proportionally. The jockeying between Rubio and Bush — one-time close political allies in the Sunshine State — underscores what will soon become the dominant narrative after the Iowa caucuses: Who will become the choice of the party establishment?

“It will probably thin out to Jeb or Marco,” said Rep. Adam Kinzinger, R-Ill., a top Bush surrogate. “You’ll start to see some clarity in a couple weeks.”