The six-year mark in an administration is traditionaly the time when at least one (but often several) of the President's underlings or associates goes to jail.
Bush 43 won't have a sixth year, but some of the offenses made on his watch have been so aggregious that several administration officials are sure to face charges regardless of whether Bush is reelected.
Of course, it would be nice if Bush could match Nixon's record (vice-president convicted and put on probation; attorney general in the slammer!) but we'd better not get our hopes up too high.