The fact that Bush fired some attorneys has nothing to do with this. The Dems are claiming foul simply to justify an investigation. The main purpose is to get Rove and others under oath. It will be determined there was no "crime" committed but there will be a number of claims of lying under oath and obstruction.
It's utter B.S. And the document dump by DoJ on Congress proves it. Even the NYT couldn't find the pony today.