TNR's Noam Scheiber, citing former Texas congressman Martin Frost, makes two points that suggest Texas is looking better for Obama than polls suggest. The first is this:

1.) Don't overlook early voting, which has been significant here. (More than one million people voted early in Texas, versus only 800,000 who voted here overall in 2004.) Unlike the February 5 states, the demographics of early voting seem to favor Obama. That means a chunk of his now-vanished lead in the polls has been locked in.
The same argument was made about Clinton before some of the earlier primaries, and it's based on a misunderstanding of how polls work. Pollsters take account of early voting by asking, "Who are you planning to vote for on Tuesday or, if you've already voted, who did you vote for?" So early voting doesn't change the math, and the later polls are more reliable predictors than earlier ones.

Scheiber's second point is a bit more cheering.