They exist. I guess I'd have counted as one of them in a loose description. And this passage from Randy Barnett makes sense to me:
Other libertarians supported the war in Iraq because they viewed it as part of a larger war of self-defense against Islamic jihadists who were organizationally independent of any government. They viewed radical Islamic fundamentalism as resulting in part from the corrupt dictatorial regimes that inhabit the Middle East, which have effectively repressed indigenous democratic reformers. Although opposed to nation building generally, these libertarians believed that a strategy of fomenting democratic regimes in the Middle East, as was done in Germany and Japan after World War II, might well be the best way to take the fight to the enemy rather than solely trying to ward off the next attack.
Moreover, the pro-war libertarians believed there was "legal" cause to take military action against Saddam's regime--from its manifold violations of the ceasefire to firing on American planes legally patrolling the "no fly" zone and its persistent refusals to cooperate with weapons inspections. Saddam's regime was left in power after its unprovoked invasion of Kuwait on these and other conditions that it repeatedly had violated, thereby legally justifying its removal by force if necessary. Better to be rid of Saddam and establish an ally in the war against Islamic jihadists in the heart of the Middle East, the argument goes, and then withdraw American troops.
Yes, but. The "but" gains traction from the events of the past four years and the appalling mismanagement of the war. It has chastened any rational interventionist's conviction, especially libertarians', as Barnett rightly understands. Jeffrey Tucker explains here.
Barnett, however, still believes we should pour money and troops into the sinkhole of Iraq. Why?
They hope that the early signs of progress in this offensive will continue, so that American and Iraqi forces can achieve the military victory necessary to allow the Iraqi government to assume responsibility for protecting the Iraqi people from terrorists, as well as from religious sectarian violence.
But the Iraqi government is a key propagator of sectarian violence and it is largely controlled by Shiite militias. There is no way Maliki or whoever poses as an "Iraqi" "government" will want to protect their sectarian enemies from sectarian violence. That's the problem. The argument for the surge rests on an abstract fantasy.