Anti-Torture Amendment, Veto Threat, and Intrinsic Evil?

The administration continues to push (see here and here) to weaken -- and threatens to veto -- the McCain Amendment that forbids the use of "cruel, inhuman or degrading treatment or punishment" against anyone in U.S. government custody anywhere.  Is there any argument that the administration's position can be squared with Catholic, or more generally Christian, moral thought?  Can defenders of the administration make any argument -- as they did concerning the invasion of Iraq -- that this is a question of prudence rather than intrinsic evil?

Tom