Bush has the advantage of a Congress and Senate who are mostly on his side. Which is why there haven't been a slew of special prosecuters gunning for him and everyone in his administration, despite ample incidents that could have justified doing exactly that. (Note: Ken Starr was far from the only special prosecutor aimed for Clinton and his staff, he was merely the best remembered.)
Of course there is positive feedback from this. For instance said prosecution would have provided plenty of news coverage to distract the President from his top priorities, and make his messages harder to get out.
Given what happened to Clinton, this is not a small difference.