So don't give the government the power to be corrupted with.
What's more likely, that companies won't fund people who can't do anything for them, or for a country of 300,000,000 over 50 states to perpetually elect 100s of people on all levels who keep their promise to never be compromised, until the end of time?
People can be corrupted, companies can use corrupted people who can benefit them and there will always be a multitude of ways to make that transaction complete, even before and after being in office.