Juliet Lapidos thinks it would set a disconcerting precedent:
It must be the case that many Americans recognize his contortions, and will vote for him regardless because they don’t like the president. That’s their right. But if Mr. Romney wins, he’ll set a nasty precedent. Candidates will be justified in assuming not only that they can lie, but that they can tell different lies to different audiences from week to week, and voters will actually reward them.