Eh -- the post just seems to manage to mangle some of the main historical lessons of Vietnam; recycle Goldberg's morally deficient misunderstanding of Obama's position; and confuse the war in Iraq with the more general war on terror under the spurious rubric of a 'war on jihadism', even though more sensible voices are waking up to the dangers of this confusion. (No such voices yet in evidence among the GOP presidential frontrunners, alas.) It seems to me more a profound inability to learn new lessons, rather than a list of real lessons learned.

Really, the Dreher post that he links to is just tons better, as are a string of related posts on Andrew Sullivan's site, e.g.,
http://andrewsullivan.theatlantic.com/the_daily_dish/2007/07/i-no-longer-b-1.html

I also strongly recommend the ever-brilliant hilzoy:
http://obsidianwings.blogs.com/obsidian_wings/2007/07/lessons-learned.html