Time to update my previous work on state-level predictors of Obama support. It turns out that Indiana and North Carolina were strikingly consistent with the trends in racial voting we’ve seen thus far. Here is a graph of total white and black support for Obama by the state’s black population (click for an enlarged version):

The lines are fractional polynomials fit to the data before yesterday’s primaries and the shading represents 95% confidence intervals. As you can see, the black vote in Indiana slightly overperformed for Obama but the other results fit almost perfectly with the predicted values.

Update 5/7 3:11 PM: To answer Rob’s question in comments, the y-axes represent the share of the total white+black Democratic vote received by Obama from whites and blacks, respectively. For instance, the total white vote (the left y-axis) is calculated as Obama’s percentage of the white vote multiplied by the proportion of the white+black electorate that was made up by whites. The total black vote is defined analogously.

The simpler graph below tells a similar story:

Update 5/7 10:38 PM — Here’s an equivalent graph to the top one using just Obama’s margin over Hillary in the white vote (corrected after Josh pointed out an error in comments):