If Sonny Landham is where you’ve been seeking a defense of libervention, then you haven’t searched competently.
Type “defending libervention” into Google. The top result — by me — has stood unrebutted for over two and a half years. I’ve asked repeatedly for a point-by-point rebuttal and have never seen it. Do you think you can come up with one?
You apparently haven’t read e.g. Brink Lindsey, Randy Barnett, Tom Palmer, or Jacob Levy on libervention. Quick, what do you consider the least unpersuasive defense of liberventionism that each has written? Or do you admit that you simply haven’t read them at all?
If this reading list is too long, then at http://www.cato.org/events/041022conf.html you can watch a video of prominent libertarians debating the invasion of Iraq.
There’s simply no excuse for claiming that reasonable libertarians cannot disagree about whether the need for a liberty-loving polity to defend human liberty vanishes completely at lines drawn on maps by statists.
So far, I’ve only been able to find one Libertarian (hi Mik!) with the intellectual fortitude to say: “The U.S. military should never be used to depose a genocidal totalitarian WMD-using ballistic-missile-firing neighbor-annexing terrorist-funding sadistic maniac who defiantly persists in what the Security Council declares to be ‘material breach’ of his agreement to be inspected for cessation of his admitted earlier secret WMD programme.”
Who’s interested in becoming #2?