You can see in the national polls over the week before Obama's March 18 speech a decline in his favorable ratings, and a decline in his showing against John McCain and Hillary Clinton. The hypothesis forms that he has been losing to some extent the support and to a more important extent the enthusiasm of Millennial voters. The March 18 speech was an attempt to get that back, or at least to limit the damage.

Did it succeed? I'm not sure. Obama portrays Wright as the voice of black America for one generation, one generation that is pretty much on the way out, and himself as the voice of black Americans and of all Americans for a new generation.

But another version comes through. Readers of Obama's gracefully written autobiography, "Dreams of My Father," have been surprised to find that it is the story of a young man who wants to embrace rather than transcend his blackness. Joining Wright's church was part of that embrace.

And observers of Obama's political career will note that joining that church gave Obama political connections in the all-black South Side that he lacked as guy who arrived in Chicago from Columbia and Harvard Law, and gravitated to the mostly white university community in Hyde Park. The 76 percent black state Senate seat he won in 1996 (after getting his opponents' names removed from the ballot) included Hyde Park, but most of its voters were on the all-black South Side.

So is Obama a transcendent leader or just another politician? Millennials who have fervently believed he is the first may, after watching Wright on YouTube, wonder whether they have been wrong.

My own answer is: both. He embraced Wright for 20 years, out of something like idealism, and got something out of it. Now he is making a generational pivot away from him, with notes of idealism, and is getting something out of that, too. I'll be watching the Millennials in the next exit poll. I suspect that Democratic super-delegates will be, too.