Typically, the clergyman with the highest profile in the country is chosen to give an inaugural invocation. Today that happens to be Rick Warren. It has nothing to do with any ‘political benefit’ to Obama. It has everything to do with asking for God’s blessing on this country as we peacefully transfer power from one Administration to another. That process is much bigger and more important than any one man.
Would you have Warren or anyone else NOT want God’s blessing on the new Administration? I don’t wish Obama success, but I sure do wish God’s blessing on this country that will be in his and his Administration’s hands.
I think the “clergyman with the highest profile” is a rather subjective determination.