One thing I've always found amusing about US is that bribing a normal person is illegal, as it should be, but bribing a politician/Congressman via campaign funds and lobbying is legal.
Is it bribing if there isn't a quid pro quo? I can give a congressperson a bunch of money with a note attached saying "Don't vote for bill XYZ", but there is no promise or even acknowledgement from the congressperson that they will do anything at all for you.