in terms of getting elected and potentially stopping war or not stopping war then his advisers, lobbyists, security councils, secret services, people with higher security clearances than the president - take your pick. I think the idea of the elected man being all powerful in ways to reign in the industrial military complex is rather naive in this day and age. Especially when neither could be described as all about the peace in their respective terms in office. Whatever their electioneering said at the time.