They all become politicians after they get elected.
There are very few angels that don’t get coopted, and to some degree, corrupted by the system and the environment it produces.
To survive in the swamp you have to eventually adapt yourself to the ways of the swamp.
That’s why sending new people in Washington doesn’t change much, other than the people that go there.
And I'll add to that ... what you think their "beliefs" are don't amount to jack. It simply doesn't matter what their beliefs are. Their "beliefs" are what Washington tell them they are.
When they get to Washington they are told how it's going to be. They may throw a bone to their constituents from time to time, just to keep them hopeful that "their guy" is in office, but their campaign donors and the System is who tells them when to jump and how high.
I'm wondering how many election cycles and the resulting disappointment in who you thought would change things it's going to take before people get that Republicans and Democrats are on the same side, which is the Government Industry.