If Obama wants to waste time prosecuting the previous administration, in four years they won't be much to show for achievement for Obama except making payback to the Republicans. I suppose he thinks that will be good enough to win a second term.
Obama and his rats will have four years to consolidate power. They have had a generation to perfect the art of political destruction. To these people, the ends justify the means.
It is simple. If they think prosecution of Bush administration officials will advance them toward their goals, it will happen. These are dangerous people devoid of any restraint, morals, ethics, or humanity.