Rezko' story is interesting but in my opinion he was just another long time political operator who got sloppy and is now being forced to pay the price.
I don't think there is much of a case for saying that Obama is involved in Rezko's indiscretions but I fully expect that those who would like to see Obama defeated in the fall will try to raise that argument, and if they are ignored I would expect them to shout louder, and maybe even hold their breath.
There are, in contrast, major issues that should be discussed and debated in the Presidential Campaign such as the economy, the war in Iraq, medical insurance, the environment to name a few.