The bottom half of this poll is more interesting than the top half, but we’ll get to that in a second. The headline: For the fourth time in two weeks, a national survey shows Perry with a double-digit lead over Romney. The worst Perry does in any of those four polls is 25 percent; the best Romney does is 18. In three of the four, Perry’s in the high 20s while Romney’s stuck in the mid-teens. Mitt’s first chance to stop the bleeding will come next week at the Reagan Library debate; if Perry rocks that and his lead increases, Romney will have to start attacking — unless of course Palin jumps in and starts siphoning off some of Perry’s base. At this point, without her, Romney’s in trouble.

Two interesting data points from the crosstabs that don’t fit the “intellectual Romney vs. populist Perry” media narrative:

Don’t read too much into those — the margin of error for these sub-samples is enormous — but for what it’s worth, Perry leads Romney not only among his own ostensible base but among Romney’s too, crushing him among college-educated voters and leading narrowly among non-tea-partiers. In Gallup’s recent poll, Perry trailed Romney within that latter group by just three points; here he has an outright lead. Lay down a marker on that now because if Perry stays strong among that group after another month or two of media vetting, Mitt will be desperate.

But like I said, the interesting stuff’s at the bottom half of the poll. Behold:

Besides Perry, the only candidate in the field who’s improved steadily over all three polls is, er, Newt Gingrich, who’s stuck in single digits and has gained a grand total of two percent since last month. Herman Cain and, surprisingly, Ron Paul have both seen their support cut in half since Perry jumped in and started soaking up the tea-party/small-government vote, and despite (or because of?) the endless flattering media coverage, Huntsman’s bled three points to settle in at … one percent. He’s actually polling worse than Gary Johnson now. In fact, according to another set of crosstabs, if neither Palin nor Giuliani gets in then Huntsman still polls at just one percent — which would tie him with Thad McCotter. Huntsman’s potentially an asset to Perry the same way Palin is to Romney, as someone who can hurt his chief competition by weakening him in his stronghold. If Huntsman was at, say, eight percent here, the combo of Perry’s lead and Hunts’s uptick would birth a huge round of “Romney underperforming, in danger in New Hampshire” stories. Instead, thanks to Huntsman’s weakness, Mitt’s still a prohibitive frontrunner in NH unless Perry himself decides to go for broke there, which is risky in case he flames out badly and ends up limping into South Carolina. What Perry needs is his old buddy Rudy to jump in and go after Romney in New Hampshire on his behalf. Who knows? Maybe there’ll be an attorney general job in it for him down the line.