It is possible since people can just vote out the angry president for their country who starts war. But, if the people decided to vote in a president who is more likely to starts wars then it can be not as peaceful.
Although, there are groups like Socialists, Communists, and Radicals which dislike Democracy, so I can see more fights with Radicals on a local level like street fights.
I doubt it, if you got someone like Fidel Castro at your head then he/she won't step down quietly and then another nation will want to step in to help take him/her down and before you know it, it's a damn civil war just like what's going on in Iraq.
People can be forced to vote via violence. Many African leaders got in via using scare tactics to get people to vote for them. So it won't make much difference.
