User blog comment:Callofduty4/CoDWiki news - September 11th '11/@comment-3171236-20110911220531/@comment-3472264-20110911223229

I'd argue that 9/11 was worse, because Pearl Harbor mainly took military causualties so technically was conventional warfare but in 9/11 we took thousands of civilian casualties, and the rules of war prohibit the unprovoked attacking of civilians.