I respect Walzer and his book 'Just & Unjust Wars' hugely, but he errs on why it was right to kill rather than try Osama. In a war the first job for the defensive side is to save its population by destroying the aggressor's ability to attack. In that endeavor, eliminating enemy leaders is legitimate. Only when the aggressor has been stopped can the long process of trials begin. America is even now in an active war with Al Qaida, and eliminating Osama was a legitimate and urgent step in stopping its
U.S. confirms ISIS computer expert killed in air strike (Reuters)
from the article: 'Goldstone Report failed to address difficulties of asymmetric warfare'