Voters are really focusing now, and I think Trump may have hit a high water mark in NH. The not-Trump vote is looking to coalesce around a candidate, and that likely is Cruz or Rubio. Given Cruz’ stronger stand on immigration over Rubio, plus his experience as a SCOTUS law clerk and arguing cases before the Supremes, I’d give him the edge. Complicating factor is Jeb staying in the race well after his “use by” date and the impact that will have. No matter what, any ‘Pub candidate — Trump included — is preferable to the two Communists barfed up by the ‘RATS.
Polls show Trump is even higher with "second" choicers, putting him up above 50 percent. If Trump were to drop out, Rubio would move into second. Ted Cruz has a very narrow appeal.
With Trump in the race, that is the only way Cruz stays in second, and at that, maybe not even for long.