Texas Gov. Rick Perry has a new staff. He released an economic plan that got generally positive, if not rave, reviews. He hasn’t had to undergo a debate ordeal since the Las Vegas debate a couple weeks ago. He’s got some ads up in early primary states.

However, there is no evidence that voters are giving him a second look.

He’s still in single digits in national polls (behind not only Mitt Romney and Herman Cain but, in many of them, Newt Gingrich). In the early states his numbers are even worse. Using the RealClearPolitics averages, he is at about 7 percent in Iowa, 3 percent in New Hampshire, 10.5 percent in South Carolina, 7.5 percent in Florida and 5.5 percent in Nevada.

His supporters would say that his ad campaign hasn’t really gotten underway, and that the oxygen has been sucked out of the race by Cain. Perhaps, but Cain’s prominence at the top of many polls seems to be a central problem for Perry. If the Texas governor can’t grab a share of Cain voters, how’s he supposed to move his numbers up?

It’s possible that the exercise is fruitless and voters, fairly or not, have decided they don’t like Perry or he’s not up for the job. But if he’s not ready to concede that, should Perry logically be taking on Cain?

There are surely reasons why that’s dangerous. In general, a candidate with likability problems risks a backlash when he takes on a well-liked candidate. It may be doubly hard to attack Cain when the conservative base feels that it’s a point of honor to defend him. And there’s an argument to be made that there is virtually no issue on which Perry can get to the right of Cain.

Cain’s closer to the Tea Party ideal (a non-politician), has a line so hard on immigration that he’d consider electrocuting border-crossers and has a tax plan that is simpler (sort of) than Perry’s. It’s also tricky for Perry to attack Cain as a foreign-policy ignoramus since his own knowledge in this area is thin. (Compared to Cain, I grant you, Perry seems like John Bolton.) Perry can’t even make the argument that Cain is too gaffe-prone, given his own debate follies.

What’s left? Well, he can try the competency argument. Do conservatives want a candidate who has won reelection (rather than lost his only campaign) and governed something? Perry would argue Cain’s just too big a risk. That’s the tactic that Rep. Michele Bachmann has been taking. (“This is the year when we can’t have any surprises with our candidate. We have to have a candidate that we can know when we put them into office we can trust them with their record of what they have done and who they are.”) Cain, the argument would go, is like betting your mortgage money in Vegas. He’s just not equipped to get through a general election against the Obama attack team, Perry would say.

There’s no guarantee this will work, of course. Sometimes voters just don’t like a candidate and rehabilitation isn’t possible. But if his numbers don’t begin to move significantly or Cain’s numbers don’t collapse in the next couple of weeks, Perry will have no choice.

If he finishes third or fourth or worse in Iowa, he’s through. Right now Cain’s got Perry’s voters, and the Texan can’t win without getting them back.