Cold War.
The two adversaries with traditional militaries that were basically sane and logical...and neither was into self-immolation if that could be avoided. Despite the ideological differences, both sides considered the enemy people they could deal and negotiate with. It gave us Tom Clancy, James Bond and a whole other host of wonderful spy fiction.
The motivation and tactics of the terrorists fall outside the diplomatic and military norms of statecraft, which results in our side resorting to responses that also stretch the limits. The war on terror is real and I believe it needs to be waged, but I hate it. It has given us two excellent movies in which the good guys need to act basically like cold-blooded murderers.