[germinalphrase]

There is a perspective out there that says our current extremity of partisanship is actually a product of the parties themselves becoming weaker. When parties were strong, they had greater leverage over their members so the party could be whipped more effectively on compromises. Now - the efforts to reduce party influence over their members (smoke filled rooms, etc etc) has led to more and more extreme members and leadership has fewer levers to pull them towards the center.