Senator Russ Feingold (D-WI) spent much of the Bush administration questioning just about everything they did as giving too much power to the Executive branch. Today he called the Obama White House to task for some of the people he has named to act as Czars.
Of course he did excuse many of the appointments, something which I doubt he would have done in the Bush years, but at the same time he has been one of the view voices on the left to question if Obama has gone too far.
His statement is here