After my blog post in which I attributed Rick Perry's demise to his sinking in the debates like a Texas-shaped paper weight chucked into the reflecting pool at the Lincoln Memorial, a Perry supporter I know emailed to say it wasn't true because debates really don't matter much in presidential races. He even had some historical data to back up his claim.

However true that conventional wisdom was before 2011, it does not apply this year. The debates are where Republican primary voters are learning about the candidates this time. That's because of the tremendous increase in the number of debates and the decrease in widespread ground campaigning in the early states. Also, though I'm not an expert on ad buys, it seems to me there are fewer TV ads so far this cycle.

Candidates are tailoring their campaigns to the debates to a large degree. They're investing a great deal of time and resources in debate prep and in fund-raising for future TV ads, so they're campaigning on the ground a lot less. Also, they don't want to get caught in a YouTube moment, which I think is contributing to the decline in retail events. So this year the big action has been on the debate stage, which helps explain the Newt surge. He's great at debates, but probably wouldn't be as strong at retail campaigning.

With retail campaigning so sparse this year, candidates have been able to translate strong debate performances into rising poll numbers and rising bank balances. Candidates who have done poorly in the debates have seen their support erode in part because they aren't making as many non-debate opportunities for themselves to show that they have other strengths.

Perry, for example, is spending most of his time raising money instead of doing the retail campaigning necessary to win in Iowa or New Hampshire, and which is one of his great political strengths. He seems to be planning on winning with large TV ad buys down the calendar.

The knock, primarily from the Perry campaign but also from some others, that being a good debater is not necessarily important is, I think, transparently incorrect. Persuasion is and always has been a highly important political skill. Simply being right on points is never, ever enough in a republic. You have to be able to convince people who disagree with you that you are right.

As states were debating whether to ratify the Constitution, Connecticut's assembly was divided. Many in the western part of the state opposed ratification, and they argued strongly against. But the anti-Federalist farmers and shopkeepers simply were no match rhetorically for the lawyers and educated eastern elites who argued very eloquently for ratification. That basic dichotomy played out in other states too, to one degree or another. The creation of our very form of government depended on the power of persuasion, and all of our big political issues today depend on it as well. So debating ability is no small matter. It is not the final measure of a candidate, but it is an important one, especially this year.