McCain has first hand experience in political corruption since he was a part of the Keating Five who while taking all sorts of gratuities and bribes helped sink the Saving and Loan business.
John McCain currently has a 67% approve/28% disapprove poll rating in Arizona with 5% not sure.
Contrast that with Arizona's junior senator, John Kyl who is at 46% approve and 39% disapprove with 15% not sure.
Survey USA polling data.