but McCain's position might well be reasonable.  His argument is that we shouldn't restrict CIA operatives only to those tactics in the Army Field Manual, because then they may be unable to use other tactics that aren't torture but that aren't listed in the Manual.  

In assessing his argument, then, we'd need to know what kinds of tactics are neither a) torture; nor b) listed in the Manual.  If there's even one tactic that satisfies both of those criteria, I think his position is perfectly reasonable and fairly strong on the merits.

As mentioned, I wouldn't say that outside a space in which I know my interlocutors are (D)s; there's simply no reason to hand a reasonable argument to the opposition.