One common objection to libertarian philosophy and anarcho-capitalism is when it comes to defense and security. Critics claim the military is something than only a government can provide. This misconception comes from either personal bias or a lack of imagination. If the military is privatized, defense and security will actually become more efficient and cost-effective, saving money for those who pay to support it.
In an anarcho-capitalist system, security and defense expenses would be completely voluntary. Individuals would pay for the military and defense services they choose. Most everyone would probably end up paying for some degree of defense, in which case you might argue: what’s the difference between that and federal taxes? The difference is you’d pay far less for at least as effective service (likely more effective).
You’d only need the bare minimum defense and security. So much of military spending is wasted on foreign affair interventions and on excess weaponry that will never be used. The government-monopolized military is incentivized to expand forever, to more countries to get more money from taxes to intervene more, causing more wars, to in turn further expand its size and scope with more weapons and technology, which means more taxes. It’s a never-ending cycle.
However, with a privatized military, there would be no incentive for this constant intervention and expansion. People can choose where to spend their money, which would be basic defense and security. That’s all people really want: to be safe at home. With individuals directly paying for their defense and security, that’s what they’ll choose. Very few people will voluntarily pay for a thousandth nuclear warhead when a dozen will do. Likewise, few will want to fund interventions in countries they’ve never visited.
The next objection is that isolation is not realistic and sometimes intervention is necessary, such as to stop the Holocaust in World War II. First of all, the rise of Hitler and the Nazis in Germany were a result of previous intervention in World War I. Regardless, if there does arise a foreign affair that some Americans truly do want to intervene in, then those individuals can voluntarily choose to spend their own money to hire private military forces to intervene in a foreign country. Then they will be at fault for any repercussions that may follow. Those Americans who do not support that intervention are not forced to fund it through their taxes.
When forced to penny up their own dollars, most people will come to realize that most foreign interventions are not necessary and most often cause more problems than they solve. With less war abroad and more freedom at home, there will be more peace and prosperity around the entire globe.