Texas Governor Rick Perry has only officially been running for the presidency a few weeks and already he has achieved what no other Republican candidate has managed: He actually beat President Obama in a two-way national poll, out this past week by Rasmussen. (Perry got 44 percent to Obama’s 41 percent.) To date, Republicans have only bested Obama on the so-called generic ballot, where prospective voters are asked to decide between President Obama and “the GOP candidate,” and even then only intermittently — Gallup’s August generic ballot has the president with a six-point lead over his imaginary alternative. The fact that a faceless and nameless Republican champion has been faring better than any of the real flesh-and-blood candidates has fueled months of speculation that the GOP’s 2012 field was still wide open. Now that Perry has fully rejiggered the political calculus, perhaps it’s time to move on from the who-will-run guessing game stage of things to the equally overanalyzed and obsessively forecast who-can-win part.