Why would anyone want to kill him?

I recall when hearing about Paul Wellstone's plane going down thinking they will probably say its possibly terrorists and do an investigation, no investigation into terrorists connection and that makes me suspicious and then after reading this article I became even more suspicious www.alternet.org..../story.html?StoryID=14399
But surely his one vote would not make that much of a difference that someone would kill him. What are your theories?