Which is valid, I think, but that argument falls down as soon as you're trying to argue the question as policy rather than ethics with someone who's convinced that it is morally justified. Even if they only believe that it's morally justified in the most desperate of circumstances, or that it's still a moral wrong but that it's the kind a leader must be willing to take on his conscience for the greater good of the nation, they're still out of the realm of "totally morally impermissible in all circumstances."