Do you really think the war industry would just roll over while a pacifist won the US presidency? These people don't have the same boundaries as normal humans. The DoD has engaged in probably the most expensive propaganda campaign in history to legitimize their activities, and any anti-war candidate would have to survive this barrage of money against them. And I seriously doubt that using violence, even against a president, is out of the realm of possibility for them. Every US president knows that they will make serious enemies, at home and abroad, if they cancel arms sales to countries like Saudi Arabia.