There are many things to be said about Obama's choice of Rick Warren to provoke, er, invoke, er, deliver the invocation at his inauguration. Sarah Posner says some of them in the Nation:
There was no doubt that Obama, like every president before him, would pick a Christian minister to perform this sacred duty. But Obama had thousands of clergy to choose from, and the choice of Warren is not only a slap in the face to progressive ministers toiling on the front lines of advocacy and service but a bow to the continuing influence of the religious right in American politics. Warren vocally opposes gay marriage, does not believe in evolution, has compared abortion to the Holocaust and backed the assassination of Iranian President Mahmoud Ahmadinejad.
And. The hits. Just keep on! Coming!
J-Mom (aka J-Mom, PhD aka Dr. J-Mom aka Prof. J-Mom) had this excellent hypothesis: since Obama is enjoined from saying too much about the Blagojevich scandal (hey-oh! did I spell that right on my first try?) and people keep trying to hang it around O's neck somehow, despite much proof of anything substantive to hang, he used his political savvy and determined that starting a tempest in a teapot was a wise way to go. Something to distract people from a circumstance beyond his control about which he can do little, by giving them something else to get outraged at. Now, to be sure, I am among the camp that thinks his choice of Warren is substantively bad and an affront to gays and those who support equal rights for humans of all flavors regardless of what other consenting adult they wish to marry, but strategically, it is a tempest in a teapot. That is, it sends a signal that is worrying, but if it really were a "wag the dog" type move, it would be in the knowledge that while this may cause discomfort, he can win back those he loses on the Left through actual substantive action later on. Which is absolutely true -- this is affronting, but if he follows with actively promoting gay rights when his administration actually starts, well, all wouldn't be forgiven, but enough would be that this would be a wise wager on his part.
I don't know that J-Mom, Phd is correct, but I don't know that she's wrong, either. It's a fascinating hypothesis, and one practically unresolvable barring a personal admission from P-E B. H. O.