I don't think your example is strong for the weak/strong link.
- It is their platform of what they want to do. Just because they say they will work towards a thing, doesn't mean that they are saying their opponents will not work for the opposite, instead it is saying if you vote for the others they will work in the opposite direction.
- Problems with the system(needing 60% to actually pass it) isn't a comment of the strength of the opponent, rather a weakness of the system.
I accept you want to think that the left is authoritarian, but for the most part that is not true in American politics.
Numbers 5:11-31. Here's a Wikipedia Article about it.