[krapp]

Libertarians tend to accept that coercive force is sometimes necessary, particularly when it comes to property ownership and enforcing contracts, although they also sometimes disagree that a state and monopoly on force are necessary for the coercion.

To this end, Libertarianism sometimes seems to me like a weak or pragmatic form of anarchy.

[gbacon]

Libertarians reject the initiation of coercion or violence but accept forceful response — at the gentlest intensity necessary — to repel such invasions. For example, a libertarian would be fine with a homeowner shooting dead an armed robber who had broken in.

Ludwig von Mises was a minarchist, i.e., he advocated for the smallest state necessary. His student Murray Rothbard referred to himself as an anarchist or an anarchocapitalist.

Of course, Rothbardians and Marxists mean entirely different concepts when they use the term anarchist.