There are no bad politicians, until after they are elected.
You see, it is the system that is bad and creates the vortex through which almost all politicians become bad, with very few exceptions.
What is that vortex you ask?
As it is there is very little in the way of accountability in the US gov't therefore the inaccountability is encouraged, not discouraged as it is in the private sector.
If a private business performed like the US gov't it would have failed long ago.
If the employees and employers lied to each other, stole from each other, and did very little in the way of honest production how long before the business would fail.
As long as people think they can vote newer and better people to "fix" a system that is inherently flawed the inaccountability will continue.
This is so obvious it is impossible for intelligent people to not be aware of it.
A vote for a politician into a flawed system is a vote against yourself.