I think that I will use the following from Don Boudreaux the next time I receive a “you don’t support the troops” emails:
Libertarians understand in their guts that flags, anthems, marble domes and columns, fancy titles, embassies, and majoritarian-voting procedures do not transform human beings and human institutions into something higher than human beings and human institutions.
There’s nothing special about the policemen who protect my house from burglars, my son from kidnappers, and my wife from rapists. There’s nothing special about the troops who protect us from foreign armies and terrorists. These activities are important and valuable when done properly. But there’s nothing special about them. Nothing about these activities gives the people who carry them out any exceptional claims upon our affections or wallets.
If the policeman or soldier agrees to render unto me a certain degree of protection in exchange for $100 of my money, neither of us owes anything more to the other as long as I pay him $100 and he performs his contractual duty accordingly. I owe him no special allegiance just because he specializes in using force to counteract force. Nor does he gain superhuman knowledge or wisdom just because he is a force-specialist.