This is just the beginning, by the way.
Bushco’s power has been steadily eroding for months, and last Tuesday set the stage for what should be (emphasis on "should") a battle with a no-longer-compliant Congress to set policy and attempt to right some of the more egregious wrongs of the last six years, ensuring that the erosion will continue.
And then, when this nightmare of a presidency is finally, mercifully OVER (and their power is gone), Bush, Cheney and the other criminals won’t be able to claim immunity from prosecution in the International Criminal Court.
I believe that none of these people will see a second of jail time, of course, but knowing that they have been punished by the international community (for reasons outlined pretty thoroughly here in Rumsfeld’s case) will be justice of a sort. And that’s probably, short of impeachment, the best we can expect.