Stuart Rothenberg at Roll Call is betting on Cruz or Rubio albeit for the very different reasons quoted below.
I continue to believe that either Cruz or Rubio will be the nominee, and that there is close to a 75 percent chance that one of them will be nominated. I’m not certain which one is the favorite — my guess changes from week to week — but they both have clear paths to Cleveland.
Cruz is well-positioned for Iowa and should do very well on Super Tuesday. As the preferred candidate of evangelicals and social conservatives, he could also be the favorite of anti-establishment tea party voters if and when Trump exits the race.
Rubio has potentially broad appeal in the party, but his strength ultimately rests on his appeal to pragmatic conservatives. He is the most likely hopeful to rally the Bush/Romney wing of the party, and his potential strength in “blue states” (many of which have winner-take-all primaries) gives him great upside potential.
Both are scary prospects but I suspect he is right. Check out his analysis of the rest of the pack.