Some Republicans are almost as bad as Democrats in disparaging libertarians. To hear them, the word "libertarian" may as well mean "anarchist."
For a well written article about how libertarians want a balanced, limited government, not an absence of government, see Richard A. Epstein's Setting Krugman Straight.
In order to set the stage for this critique, it is necessary to first establish how libertarians understand free markets. Most emphatically, these markets do not operate in a vacuum. They require that we have clear assignments of rights to both human labor and external objects. The standard position here is that all individuals own their own labor and the various resources, both physical and intangible, that they acquire either by initial capture or by transfer from a prior owner. Its basic system of exchange must be protected by vigorous rules that prevent all self-interested individuals from disrupting voluntary transactions. There must be formalities with certain classes of contracts to increase security of exchange. And there must be strong rules to prevent bad actors from bypassing the market by seizing things that do not belong to them. That prohibition against theft in turn requires the state to provide remedies against other actions that destroy the property of other persons, not only by direct blows but also by pollution. Far from rejecting these government limitations on individual activities, a responsible system of laissez-faire capitalism necessarily embraces them. A sensible libertarian is a classical liberal in the tradition of Adam Smith and David Hume. On economic issues he is no anarchist, but a believer in limited government.
For an added bonus he provided a liberal dose of Krugman bashing.
Via Future of Capitalism.