Of course, that is why we have governments in the first place (i.e. to get around those problems).

It doesn't get around those problems, DaveInNYC, it just changes the conditions under which the problems arise. Having one, really powerful actor that can dominate the Commons doesn't solve anything - if there aren't enough reasonable and enlightened people to maintain control of the government, it begins abusing the Commons itself, and anyone not completely controlled by the government lose any disincentives to act for their immediate short-term interests.

Who guards the guardians? Who watches the watchers? Ultimately integrity cannot be maintained by force. Governments only act as a solution to the problems of society as long as their integrity remains, and history shows us that it doesn't last very long.

I will further note that Libertarianism does not require a stable government, it simply requires that force is not used. That can be because force isn't a viable short-term strategy, or because an enlightened power has a monopoly on it. There is need of enforcement only when dealing with non-Libertarians.