At first glance, a reasonable libertarian might consider Glenn Reynold's enthusiasm for assassinating radical Iranian mullahs and atomic scientists to be a "small government" approach, and Reynolds might even think he's returning to his libertarian roots following his armchair leadership in Iraq. I'll just note that as a policy matter, "no government" as in no assassinations and no wars of conquests, can often be superior to small government. Maybe assassination can sometimes be helpful, but at least in the case of radical mullahs, getting caught doing what Saddam tried to do to Bush Sr. would be the exact opposite of helpful.
And then there's the small matter of whether it's ethical. I disagree with Kevin Drum (linked above) who calls all killing of civilians "terrorism". Those civilians and high-ranking politicians who are intimately involved with the military may as well be wearing a uniform and are legitimate military targets. But Reynolds wants to kill all the radical mullahs, not just high-ranking ones, and if Iranians aren't working on a bomb, then killing their scientists is also wrong. Reynold's ethical screen needs a great deal of tightening.
Assassination and other threats of force could be appropriate for an ethical or even a competent presidency to use in dealing with Iran, but that's not what we have, and Reynolds is making a mistake to encourage this behavior.