Theory one of the Newt surge is that it's caused by something about Newt, which suggests that it's real, much more real than the Cain surge or the Perry surge or the Bachmann surge or the Trump surge.
Theory two is that Newt is surging because voters who aren't paying much attention yet and mostly like most of the candidates have heard nice things about him most recently, and so they'll echo that back to pollsters -- but it has little to do with what they will do when they focus on the race, receiving information from ads and other places, and make a real vote choice.
I've seen some quite interesting and creative versions of Theory One recently, but I'm still not buying it. For example: the normally very sensible Jamelle Bouie argues that the fiasco of Newt's term as Speaker "wasn’t enough to damage his standing among Republican voters. Gingrich fought the good fight, and this gives him a lifetime pass for a whole host of transgressions that would sink any other candidate," with "the good fight" being his grappling with Bill Clinton and his perceived role in the 1994 landslide.
Which makes sense...except it just isn't consistent with the polling. Newt began the campaign with reasonable favorability scores, but they tanked after his awful spring, in which he attacked the Ryan budget, lost his staff, and everyone talked about Tiffany. The "forged in battle" story would work if Newt had retained his good personal numbers but simply lost out in the horse race polling, but that's not what happened at all.
Of course, even if I'm right about this, it doesn't at all prove by itself that Newt will collapse. What it does show, however, is that he's as vulnerable to attacks or unfavorable publicity as anyone else. And given that we also know that anyone in WH 2012 can benefit from a wave of positive attention -- that's the nice thing about the Trump surge -- there's really nothing to explain here in the first place. Remember, there were plenty of Theory Ones about each of the other surge candidates.