I have always found it hilarious that whenever you confront a libertarian about his ridiculous views on defense his stock answer is to say, "Ever heard of Vietnam ?", apparently implying that a militia is all that is needed.
Hey, the NVA and Viet Cong paid a horrendous human cost for their victory. They lived in tunnels and caves in the Iron Triangle for ten years. Would libertarians live in tunnels and caves for ten minutes ? Would people imbued with the philosophy that they don't owe anyone anything suffer and sacrifice and die the way the NVA and Viet Cong did ?
And if it weren't for Walter Cronkite, and possibly the French, they never would have had a victory.