Stephen Pinker and the long peace: alliance,deterrence and decline

It is now widely accepted, at least among academic students of war, that there has been a great and generally benign transformation in the character of war. The sort of big wars involving the world's greatest powers, those that in practice or in prospect dominated international affairs from the rise of Napoleon to the collapse of communism, are now considered to be essentially obsolescent. But to what extent is that really true?