I wonder: is there such thing as an uncorrupt politician?

i mean, by the time you reach any status, how many favors have you gotten that need repaying. does the president always end up corrupt by the time he has made it all that way? i think sometimes people would be calling in favors to be paid back and we the people could suffer from this in many ways...bad policy-financially- or just from having to go through all the criminal proceedings, once the politician is caught doing illegal things. what cha think guys????