When we think of corruption, most of us think in terms of bribery: fat bundles of money stuffed in envelopes and furtively passed to conniving politicians. And that's almost never the case. Oh, to be sure there are exceptions, such as "Cold Cash" William Jefferson (D-LA), currently serving 13 years in the slammer, but as a general rule, corruption takes much different forms.
Indeed, this was an issue of great concern among the Founders of the USA; Benjamin Franklin argued with considerable merit that elected officials should not be paid, although unfortunately that view was ultimately rejected. Franklin's wisdom, however, has been vindicated in the American political system with which we exist today: the rise of a permanent political class. The argument advanced by Franklin essentially noted that paid elected representatives would be less inclined to act for the greater public benefit, but rather toward the advancement of their own self-interests; as citizens, they should be expected to serve briefly and then return to their own productively private lives.
In rejecting that argument, the other Founders nonetheless built disincentives into the structure of government service, such as prohibiting acceptance of gifts, among other limitations. And difficult though it may be to believe, lobbying was illegal in the United States until the 20th Century. Gradually, the limitations were circumvented, weakened, and ultimately removed; old Ben was correct - paid politicians acted in their own self interest to accumulate influence, then power, and of course, financial gain.
They became corrupt.
Thus we find ourselves in the world in which we survive today. I did not say "live", nor "thrive" quite deliberately; we do neither of the latter, we merely survive as career politicians and their minions burden us with ever-increasing taxes, fees, and hundreds of thousands of regulations. They grow ever fatter while we grow ever poorer. Just for giggles, try to find one long-term congressman who is not today, as a result of his or her years of "service", a multi-millionaire. There's a reason why they fight so desperately to win re-election, and despite their words to the contrary every election cycle, it has nothing to do with you.
There are those who claim that we already have "term limits" - and it's called the ballot. The problem with that facile attempt at mollification is that it has, throughout our history, failed. It has been said that doing the same thing over and over while hoping for a different result each time is the very definition of insanity, and that seems a valid assessment. Clearly, it is time to do something different. We need term limits for all elected representatives at all levels of government.
What we have now has devolved into a racket, not a government.