Defensive force is the use of force to defend your safety, rights, or property. You have the right to defend yourself, and the right to authorize others, such as those in government, to use defensive force in your behalf. Defensive force is survival. Retaliatory Force is punishment of someone who has initiated force. If someone assaults you, you have the right to authorize government to punish those responsible in your behalf.
Retaliatory force is justice.
Some people have suggested a fourth category of preemptive force but most examples of preemptive force, upon analysis, can be placed in one of the other three categories. Libertarians are, by definition, those who oppose the initiation of force. SOME libertarians are also pacifists and decline the use of any force. Libertarianism is broad enough to encompass pacifists. All oppose the initiation of force.