The Mitt Romney path to the nomination is not available to him. Bush can’t show up with a fundraising advantage, a professional operation and a resume, then expect to inexorably grind down all the other candidates. Romney could do that in 2012 against an unprepared Rick Perry, an undisciplined Newt Gingrich and an unfunded Rick Santorum. Bush is running against a field that has about a half-dozen candidates who would have been in the top tier last time around.
Romney won the nomination despite his Massachusetts health-care plan that was anathema to much of the party. It’s one thing to have a few heterodoxies, though; it’s another to be defined by them. What most conservatives heard from Bush during the Obama years was his plaints about the GOP’s tone, and his support for comprehensive immigration reform and Common Core. Those two issues have come up over and over again during the early phase of the campaign, and while Bush has adjusted his positions a little, he hasn’t changed them.