The message echoed the one Obama delivered last week at a historically black college in Maryland. “Don’t make me look bad, now,” he said, urging the mostly African-American audience to vote.

In casting the election in such personal terms to black voters, Obama is making the kind of racial appeal – as understated as it is – that he has been reluctant to do in the past.

It’s unclear if his popularity among African Americans – 91 percent – will transfer to other candidates, particularly white ones, in November. With enthusiasm lagging among Democrats – especially African Americans, who surged to the polls to help elect the first black president in 2008– the appeals of Obama’s coattails are being tested.

“The issue here is that Obama’s popularity among black people was as much a personality cult as it was about the specifics of his political quality,” said John McWhorter, a linguist at the conservative Manhattan Institute. “The task now is to make people understand that it’s equally important for them to come out and vote on behalf of senators and governors…even if they’re not him, even if they’re not black. And that’s a tough one.”