As I have been saying on social media, both Clinton and Sanders had electoral hurdles that they had to clear. Clinton’s was to win by large margins in states not in the Deep South that are reliably Democratic or that are swing states in the general election. Sanders’s hurdle was to demonstrate that he could win in states where the portion of nonwhite Democratic primary voters was greater than a quarter of the whole.

Only one person cleared his hurdle Tuesday: Bernie Sanders.

The nonwhite portion of voters in Michigan’s Democratic primary, according to exit polls, was 30 percent. Furthermore, 21 percent was African-American. This is much smaller than the majority black vote in some Southern Democratic contests, but still sizable. More important, Sanders won a larger share of the black vote in Michigan than he had won in any of the Southern states for which there were exit polls.

For instance, Sanders won just 11 percent of the black vote in Mississippi, but he won 28 percent of it in Michigan.

Northern blacks and Southern blacks are most likely processing Sanders quite differently. As I wrote in a February column:

There isn’t one black America, but two: The children of the Great Migration and the children of those who stayed behind in the South. (Black immigrants are another story.) Having spent the first half of my life in the South and the second in Great Migration destination cities, I can attest that the sensibilities are as different as night and day.

Sanders’s early, Northern activism for racial equality is likely to have more resonance with Northern blacks, and so is his largely urban and non-Southern roster of black surrogates. For instance, more Michigan primary voters said they trusted Sanders more than Clinton to handle race relations in this country. The opposite was true in Mississippi.