On the likelihood of global war

Unusually for someone of his ilk, John Mueller has embraced one of Gingrich's numerous ideas — that defense budgets should be "directly related to the mount of threat" faced by the United States. He comes to a surprisingly ignorant conclusion:

There would, of course, be risk in very substantially reducing the military, but there is risk as well in maintaining forces-in-being that can be impelled into action with little notice and in an under-reflective manner. After all, if the country had no military in 1965, it could not have wandered into Vietnam, and the lives of fifty-five thousand Americans would have been spared. If it had no military in 2003, it would never have ventured into the Iraq fiasco and several thousand Americans (and a hundred thousand Iraqis) would still be alive. And had the country needed more time to mobilize (and therefore think) in the wake of 9/11, it might possibly have employed reactive measures more likely to have been effective at lower cost.

I think this to be a contemptuous statement, and all who support it show a vast ignorance. It's impossible, or at the very least irresponsible and intellectually dishonest, to review history and feel as though you know how it may have worked out if a certain event hadn't occurred, or, in this case, that a military hand't been there to fight a particular war. How can Mueller possibly be sure of anything he just wrote? Nobody can say the things he has just said with any degree of certainty beyond the fact that it is possible, and unless he has some supernatural power not at our disposal, he shall have to adhere to the same rules.