Chris Cillizza reminds us:

In the next 60 days, there are five presidential debates scheduled — a series of standoffs that amount to a testing ground for the top-tier Republican candidates as the campaign picks up momentum.

The debates will come in quick succession after Labor Day: Sept. 7 in California, Sept. 12 and 22 in Florida, Oct. 11 in New Hampshire and Oct. 18 in Nevada.

Cillizza also reports that, surprisingly, Texas Gov. Rick Perry hasn’t committed to any of them.

There are a few lessons to be learned from the debates. First, Rep. Michele Bachmann (R-Minn.) won admirers in the last two debates by being far less crazy and much more articulate than voters and the media expected. But, as we saw last weekend, reporters are getting more aggressive in questioning her, and the absence of clear, concrete proposals will hurt her. She now has to improve as a candidate to maintain her first-tier status.

Second, there is no Tim Pawlenty to kick around anymore. Seriously, a weak puncher allowed both Bachmann and Mitt Romney to counterpunch and thereby appear in command. As three top contenders emerge (plus a sharp-tongued Rick Santorum) the danger in directly engaging opponents increases. (Perry is going to bring up RomneyCare? Well, Romney will hit back with the high rate of uninsured in Texas. Bachmann is going to go after Perry for budget gimmicks? Perry is going to hit back on her lack of any viable budget plan.)

Third, no one is certain how tough Perry will be. He generally avoids the press in Texas, is rarely challenged from the right and doesn’t have the experience that Romney (or even Bachmann now) does at this peculiar skill. Moreover, as the new guy on the block the moderators will have all their note cards filled with research and nettlesome questions. Romney’s heard most of what they have against him; Perry hasn’t yet run the gauntlet.

And finally, there will be a time when one of the top-tier candidates will have to take on the front-runner. Every debate that passes with no gaffes or bobbles is a win for Romney, even if he is not dominating the field. When someone more capable than Pawlenty finally does go after him, it will be high drama. Does Romney falter, or does he show he’s made of sterner, smarter stuff than his opponents?

There are some who say there is time and space in the race for yet another contender. That window of time will close, I would suggest, after the next round of debates. So all stragglers had better ask themselves: Can’t I do better than the current competitors? If they think so, the debates are the perfect time to show the voters.