The concept behind the Bush campaign had the following components: (a) scare off all potential Romney Coalition rivals with overwhelming fundraising; (b) hope for competition among the Reagan Coalition candidates; and (c) outlast everyone with its organizational advantages. It failed miserably, and he is now out of the race.
The Rubio plan, on the other hand, was to hope that Bush imploded, given his obvious drawbacks as a candidate, and to build bridges to all of the factions of the GOP with an eye to becoming a consensus candidate. The first part of this has worked, due partly to his own strengths as a candidate, but more to Trump’s evisceration of Bush. Now comes the hard part: can he peel enough votes away from Trump and Cruz to win the nomination?
After the first three contests, you would have to say the answer is no. His best hope at this point is to get Kasich out of the race as quickly as possible, to inherit the Bush and Kasich voters in the establishment lane, and to win enough states with about 40 percent of the vote to get a majority of the delegates. It’s not impossible, but you wouldn’t want to bet the ranch on it.