Big trouble tomorrow night for Herman Cain: After his flukish surge in the polls, he’s apparently going to be, quite literally, pushed to the center for the Washington Post/Bloomberg debate, as Ben Smith reports. This isn’t apt to go well.

Cain, so far, has shown two strengths in debates. He’s good at pounding a very limited talking point (9-9-9!), and he appears to actually have a sense of humor. This is extremely well-suited to his usual role on the fringes of the action: The main contenders squabble (whether it’s Pawlenty/Romney, or Pawlenty/Bachmann, or Perry/Romney, or, bizarrely, Santorum/Paul, the two candidates who have actually done real debating with each other in any of the six debates so far), and when Cain gets his occasional chance to talk, he’s refreshing, either with a positive message (yes, that would be 9-9-9!) or with a quip.

When he has had to expand on his answer, however, Cain has repeatedly showed the lack of even basic policy chops. Now, he’s hardly the only one in this peculiar field with that problem. However, where (for example) Michele Bachmann will just say some crazy stuff with all the conviction she can muster, Cain’s habit is to retreat to a reminder that he’s not a politician and he doesn’t need to know anything, anyway, because he’ll just hire experts once he’s president to tell him what to do. This rhetorical trick doesn’t appear to fly very far even with politician-bashing Tea Partiers, who, after all, have very clear positions on the issues, even if those positions may be based on misinformation and myth.

Now, this is the kind of rookie mistake that can be easily fixed by good debate prep (the kind that Rick Perry is rumored to be engaged in after three increasingly disastrous efforts). But politicians aren’t likely to change what they’re doing when they believe it’s working, and surely Team Cain believes they’ve stumbled on a winning game plan. My guess is that he’s riding for a fall if he trots out from center stage the same stuff that worked so well from the peanut gallery. The only good news about this is that candidates who understand what’s happening should still be concentrating their fire on either Rick Perry or Mitt Romney, so it’s certainly possible that Cain won’t take any hits — and will therefore still not need to talk all that much. And that seems to work for him just fine.