That is a very interesting and plausible theory.
That's why we have to drag this primary out until the convention. It won't matter who wins the nomination after the convention because it will force Romney to the right on health care and it will prevent Obama from playing off of Romneycare until it is too late. Obama cannot call for the state mandate before Romney clinches the election because voters would turn to Santorum at the convention. No wants Romneycare, any more than we want Obamacare.