So the defense now is "Bush did bad things, too?"
Statement: Anything a Democrat does that a Republican has done is OK.
Given: The "OKness" or "wrongness" of an event is fixed regardless of who does it.
Assertion: Anything a Republican does is OK.
Proof:
Assume that a Republican has done something and a Democrat then does it. The Democrat did nothing wrong because a Republican did it. The Republican did nothing wrong because if it were wrong when the Republican did it it would also be wrong when the Democrat did it.
Assume that a Republican has done something and no Democrat has yet done it. The Republican still did nothing wrong because it is possible for a Democrat to do it in the future and if it were wrong before the Democrat did it then it would continue to be wrong after the Democrat did it. Even if no Democrat were to later take the same action the action cannot be wrong because if it were then we would know that no Democrat will ever take that action (because then the Democrat would be wrong) and that would give us information about the future which is not possible.
Therefore, anything that a Republican does is OK.
QED.
A corollary of this is that everything a Democrat does is OK because a Republican could later do it and we have already proven that everything a Republican does is OK.
Additional corollary: since Democrats and Republicans can do no wrong, only Independents and Third Party people will go to hell.