There is NO Republican currently running who wouldn't sign the bill to repeal ObamaCare so this shouldn't even be an issue. If a Republican congress passes the repeal (and I am sure they would) then all of the candidates currently running would, as President, sign that repeal.
I wouldn't be too sure about that. Romney the flip-flopper could flop yet again and, safely ensconced in the White Hut with 300 electoral votes in his pocket, decide that Obamacare was a good idea back when he, Romney, thought of it in Taxachusetts.
Keep in mind, too, Howell Raines's article (he was formerly editor of the New York Times, with beaucoup contacts among the East Coast RiNOcracy) in October 2008 in Conde Nast's Portfolio, in which he claimed that the Republican Establishment, talking to the 'Rat policy wonkerati via the "economic conservative" foundations, had already agreed to a national health-care plan, in order to accomplish the will of the Fortune 500 CEO's who want to dump employee healthcare plan and, they think, take those dollars right to their bottom lines.
At the time he wrote the article, the GOP mandarins were simply waiting for the children to get done with the election.
Another straw in the wind: The Tea Party brought enough new Republicans to Congress to put Boehner in the Speaker's chair, and their motivating force was the repeal of Obamacare.
But Boehner has done a bait-and-switch, and at the start of the year a) denied Michele Bachmann a place in the House leadership (he told her "it's not your turn" -- classic RiNO B.S.) and b) switched the subject of the GOP congressional agenda from Obamacare to budget and national debt issues.
Boehner won't help to repeal Obamacare, because the RiNO leadership is secretly committed to preserving it and allowing private healthcare insurance to die.
Push healthcare to the government, put it on the nation's tax bill, and shove the taxes from corporations back to the individual taxpayers -- the little people -- and let them sink or swim. Can't afford it? Better have a good funeral plan, you'll need it soon. And so on -- a bevy of future Democratic campaign themes in the making, courtesy of RiNO Establishment Central.