For this unexpected turn in what has been a steady and sure campaign, the Romney team has no road map. With just five weeks until the Iowa caucuses, the former Massachusetts governor and his advisers are trying to figure out what to do. Will they stick to their tried-and-true playbook and hope Gingrich falls on his own, just like the others? Or will Romney engage Gingrich directly and aggressively, either through ads or in a pair of upcoming debates?

“Is there enough time for Gingrich to self-destruct on his own before Jan. 3, or do you have to help it along? It’s a tough call,” said a GOP strategist who informally advises Romney’s campaign and, like other advisers interviewed, spoke on the condition of anonymity to discuss internal thinking…

The question looming over the race is whether Gingrich will suffer the same fate. Increasingly, Romney’s advisers believe he will not. They are calculating that primary voters will overlook Gingrich’s rocky career in public life — including ethics charges, extramarital affairs and a decade of trading his influence to enrich himself.

Voters “know all that, and they’ve discounted those things,” said a third Romney adviser. “The leadership of the campaign recognizes that Gingrich has got staying power, that he’s a very serious candidate.”