Don't let the anti-libertarian crowd catch wind of this! Repeat this until it is true; "Libertarians are all the same, Libertarians are all the same, Libertarians are all the same." I feel better already! LOL!
You do bring about an interesting dimension of international relations and Libertarian Government. I think there is certainly room for "empire" in dispensing life, liberty, and the pursuit of happiness outside our borders. But I really don't like the current model of oligarchial driven nation building.
For right now I am totally committed to the skinner method of foreign policy. Totally destroy the enemy in Afghanistan and demand an unconditional surrender. Then permit free market development in which parties in Afghanistan contract with private investment. If the Afghanis choose not to participate in free markets, let them live their way, not a way dictated by a Marshall Plan. The Afghanis have a thirst for liberty. To give it away or order it spoils the taste. Let them earn it, so they can respect it.