As you know, Mitt Romney yesterday shifted gears and adopted the view that the individual mandate is a tax — after his campaign said the opposite a few days ago. This is more than a story for the news cycle, however; it has important implications for how Romney would conduct himself as president.

Here’s what Romney told CBS:

“The Supreme Court has spoken, and while I agreed with the dissent, that’s taken over by the fact that the majority of the court said it’s a tax, and therefore it is a tax. They have spoken. There’s no way around that.”

As Greg pointed out this morning, conservatives aren’t at all satisfied by this change of heart. But their dissatisfaction has less to do with the substance of this debate, and everything to do with their mistrust of him. If anything, this episode highlights the degree to which Romney does not share conservative instincts, and must constantly shift positions as a result of that misalignment. Indeed, you could see the past week as a microcosm for Romney’s entire career. He’s an opportunist who is hindered by his complete inability to skate in concert with conservatives.

Regardless of how he wins — short of a landslide — Romney will have to negotiate conservative mistrust from the moment he enters office. He’ll have to assure conservative activists and congressional Republicans that he won’t betray their interests. He’ll have to deal with the expectation — from figures like Grover Norquist — that he’ll act as a signing machine for legislation such as the Paul Ryan plan. To meet these expectations and build credibility, he’ll almost certainly begin his presidency with a torrent of right-wing initiatives. Moreover, he’ll always have an eye on his right-flank — otherwise, he risks revolt.

The key takeaway from this fight over Obamacare messaging is straightforward: If Romney is elected president, political pressure will force him to govern from the right. He has no other choice.

Jamelle Bouie is a Writing Fellow at The American Prospect. You can find his blog here.