The politicians of both parties are "corrupt"...meaning they care more about themselves and their families than they do about the mass of humanity that makes up the United States.
I suspect that is because we choose our politicians (both parties) from the human population...and among humans, almost all are more concerned with themselves and their families than with the general population.
I don't think politicians are MORE corrupt than others...its just that politicians have the opportunity to use their corruption the way they do. The big shots of industry are in that same position. The man and woman in the street...just is not able to turn their "corruption" into big gains.
That all said...I HOPE the GOP is in trouble, because besides being "corrupt"...they are incompetent. They do not know how to govern...and in my opinion, we'd be much better off with the GOP serving as the loyal opposition.