When will Obama Learn?

One criticism I have Obama is his seeming unwillingness to react strongly and quickly to negative (non)stories leveled against him. One further example is James Johnson who is leading Obama's Veep search. He also had long-standing and lucrative dealings with Countrywide Financial, one of the worst offenders in the mortgage crisis. I know he wants to run a "different campaign" but he cannot respond a whole news cycle late to these sorts of things.