In fact, Mr. Perry’s lead in the polls right now is based in part on perceptions that he is electable. The recent Washington Post / ABC News poll posed an interesting set of questions to Republican voters — asking them who they thought was closest to them on the issues, and who they thought was most able to defeat President Obama, in addition to their first overall choice.

Mr. Perry led the Republican field on each of the measures. But his lead was actually larger on the electability question: 30 percent of Republican voters said they thought he had the best chance of defeating Mr. Obama, versus 20 percent for Mr. Romney. By contrast, Mr. Perry held a smaller, 6-point lead over Mr. Romney on the question of his issue positioning…

But if perceptions about electability fade, so will his overall numbers. Regression analysis of the Washington Post poll suggests that Republicans are weighing these two factors — electability and issue positioning — about equally. If Mr. Romney, rather than Mr. Perry, led on the electability question, that could be enough to push him past Mr. Perry even if Mr. Perry is a little closer to Republican voters on the issues.