The play-not-lose strategy lost Obama the first debate, and it lost Romney the third. Worse, Romney’s approach reinforced his biggest weakness: a growing sense that he will alter any position if doing so will help him win the election.

For almost the entirety of this campaign, Romney has been on the assault against Obama’s foreign policy, and all the attacks came from a hawkish perspective: that Obama was not tough enough on Iran, withdrew troops too quickly from Iraq, was inconstant in his support for Israel – and on and on.

But on Monday night, Romney couldn’t agree with Obama often enough. Over and over, he endorsed specific Obama policies. Over and over, Romney used the word “peace.” This once staunch supporter of the Iraq war declared: “We don’t want another Iraq.” Romney’s main goal seemed to be to make sure voters would not shut off their television sets end of the debate fearful that Romney would replay George W. Bush’s foreign policy.

The cost of creating this reassuring presence, however, was that doing so reinforced Obama’s attack line on Romney as an unprincipled politician. Romney’s stands on issues seem related almost entirely to the political calendar: Veer as far right as necessary in the primaries, then slam on the brakes, turn right around, and head in an entirely new direction – all in pursuit of those moderate suburban moms whom strategists on both sides see as central to the election’s outcome.

Obama seemed confused in the first debate by the New Romney (or, depending on how you want to count these things, the New New Romney). He wasn’t this time. “I’m glad Gov. Romney agrees with the steps we’re taking,” Obama said at one point, and then catalogued how it has not always been thus. Obama was particularly tough after Romney praised the killing of Osama Bin Laden. Obama noted that Romney had once said, “We shouldn’t move heaven and earth to get one man,” thereby using one foreign policy matter with which all Americans are familiar to illustrate Romney’s habit of altering his positions when doing so is convenient. In a foreign policy debate especially, a Democrat wants to convey toughness. That’s what Obama’s demeanor did.

We will know soon enough what voters make of all this, but my hunch is that Romney not only underestimated the cost of a play-it-safe strategy in the debate itself, but also misread the political moment. Romney did have momentum after the first debate, but I don’t read the polls as showing that this race was still moving his way. Rather, it was stuck, with each candidate having a chance to move the contest his way. That means that playing to win tonight was the right strategy. It’s the one Obama chose.