- defend against a foreign enemy (which means she believes there are discrete societies to which someone belongs which may be hostile to each other)
- police the nation for crime (what is the definition of a crime, Ms Rand? and does not the definition of "police" include oversight, monitoring, and enforcing the laws of the society?)
- enforce voluntary contacts between free parties (would involuntary contracts then be crimes or free-for-alls?)
I believe there is a little "libertarianism" in all of us Americans. We are the home of the free and land of the brave, the Wild West. We don't want shackles. We don't even want anyone putting a hand on our arms and saying, "Hold on, mate."
And, we certainly don't want any of our hard-earned money on anything for which we did not personally assent. Any funds spent on anything for which we do not see immediate benefit to ourselves is being wasted.
Yet, when something horrible happens to us personally, what is the first thing someone says? "There ought to be a law." "Who was supposed to be watching this? Why isn't anyone investigating why this happened?" "Who's to blame? They should be sued." "That intersection is so dangerous; 'they' should have put up a traffic light long ago." Let's close the barn door after the horses leave, shall we? Is that the role of government, to be reactive? And who's that "they?" Isn't it "we?" Aren't we collectively the government?
As Brooksley Born had pointed out, our government needs to know what's going on so that we can police crime and enforce voluntary contracts, not to rely on an honor system which by human nature is naturally imperfect and then, react to resulting chaos. There is the debate of 'a public good' to be discussed someday.