Most mainstream Americans' political principles are variations on "defend your side at all costs." An ideology without a (real) problem to solve is a very dangerous thing.

Viewing the US from the outside, it really is puzzling that in that land of freedom - where the ability of the individual to express themself is prized above all others - happens to be a place where people are pigeonholed by which one of two political parties they vote for, and it's frequently considered to be all you need to know to know everything about a person's opinions. "Well he would say that, he's a Democrat" kind of thing.