From what we've seen so far, there are two forces that will weld Jeremiah Wright to Senator Obama for the duration - our McCain-loving, back-slapping, wannabe heartland America regular guy national media...and Rev. Wright himself. While I do not think it's fair to ascribe Wright's strange and twisted vision to Barack Obama, I do think there is an unfortunate structural reason why Wright matters in the Obama story.
Barack Obama ran on a slender political resume decorated with a rich palette of rhetoric and image and vision. To his eternal credit, that vision has brought more people to the process, particularly young people. But that slim CV is the steel weld holding Wright to Obama's campaign; in the absence of experience in the public arena, Wright becomes an essential part of who Obama is. It's clear that the young politician's embrace of the older minister was part spiritual, and part strategic - bringing the kind of street cred needed to rise to the top in Chicago. I will say nothing about Obama's religious doctrine, except to note that the Senator himself has made his beliefs - and his journey in acquiring them - central to his life story, to his political brand, to his very reason for running to change the country.
Simply said, Jeremiah Wright - whatever his strange motivation in dragging his spiritual protege down so badly - is central to Barack Obama because there isn't too much more to go on; Wright is one of the key figures in Obama's life story.
In practical terms, Rev. Wright is - for now - Senator Obama's virtual running mate. He is to Obama (in media terms, not in moral equivalency) what the failed presidency of George W. Bush is to John McCain, the albatross he can't shake off.
UPDATE: I think Digby had the best description of how strange Wright's show-boating this week has been, and why he may not be going away: "Wright's latest round of media appearances have not seemed to me to be any kind of defense of liberalism or the black church or even Black Liberation Theology so much as one man's desire to deny a rival his destiny. This was personal and I find it very creepy." And Walter Shapiro makes the point that Democrats who trumpet their faith as driving them to politics (Clinton included) are whistling past the churchyard.