There is also a Lucas critique issue of how the bad guys start behaving once they figure out that the good guys are pacifist, and I don't see him discussing that either.
I do not know how relevant this is, but I believe there is a result that in tournaments of repeated-Prisoner's-dilemma games, the "tit-for-tat" strategy works the best. I don't have a reference at my fingertips, but I think I recall reading this in Howard Rheingold's Smart Mobs, and he would have had references.
These are games in which the best outcome is "cooperate/cooperate," but for each individual the best outcome comes from defecting when the other person cooperates. In repeated games, one strategy is to play "tit for tat." When the other player cooperates in this round, next round you cooperate. When the opponent defects this round, next round you defect. As I understand it, this strategy works best against opponents, either human or computers, who follow a variety of strategies.
I am not sure what tit-for-tat means in the context of international relations. But perhap one example of a state that plays that way is Switzerland. Famously neutral if you leave it alone, but well armed if you want to attack it. As Tyler says, that has worked well.
As a practical matter, I think that a Swiss approach for the U.S. would be, like pacifism, quite a departure from the way that the U.S. has conducted itself for much of (all?) its history.