More good news for the president: Gallup’s daily tracking poll today has him edging into positive territory, at 49% approval, 45% disapproval. He’s poked into positive territory a couple of times recently, but both the 49% approval and the +4 net approval he enjoyed today are the highest since the rally effect after bin Laden’s death last year.

There’s no magic number for where approval has to be for him to be assured of re-election, but generally people estimate that 48% or so approval is probably around the break-even mark, and a low 50s rating makes re-election very likely.

Keeping in mind the caveat that things can always turn around as events change, Obama’s approval pattern looks somewhat similar, if not quite as good, as those of Ronald Reagan and Bill Clinton, with approval moving into positive territory early in the re-election year. The direction is what counts.

What’s more, it looks as if Obama is now on the verge of doing better than the two most recent presidents who weren’t reelected — George H.W. Bush and Jimmy Carter — were faring at this point in their first terms.

A few weeks ago, Obama’s approval ratings were among the lowest for presidents at this stage of their terms. Now, however, he’s moving ahead of Bush, who had sagged to 44% approval over February 6-9, 1992. If Obama maintains his mid-to-high 40s level a bit longer, he’ll pass Carter, too; Carter at this point was enjoying his last period of good ratings following the beginning of the Iran hostage crisis, after which he fell below 45% and never recovered.

Obviously, there’s no guarantee that Obama’s approval will continue to improve, or even stay where it is now. Still, he’d certainly rather be where he is today than where he was four or five months ago. Unlike a lot of numbers you can look at right now, presidential approval ratings are reasonably good predictors of election results, and today that’s pretty good news for Barack Obama.