read up on the Art of War and tell him how this was the biggest strategic mistake the Nation has ever made.. tell him Ron Paul supported the fight in Afghanistan and he's using his wisdom not idealism in his opposition to the war - that it will only make things worse the longer we stay.
"...to fight and conquer in all your battles
is not supreme excellence; supreme excellence consists
in breaking the enemy's resistance without fighting."
if we want to defeat islamic fundamentalists then we must make more friends than they do - we can't give them easy propaganda by dropping bombs and invading countries.
read it up -
http://www.chinapage.com/sunzi-e.html
"If you know the enemy
and know yourself, you need not fear the result of a
hundred battles. If you know yourself but not the enemy,
for every victory gained you will also suffer a defeat.
If you know neither the enemy nor yourself, you will
succumb in every battle."
I don't think the US knows either itself or the enemy.