Bill Clinton
Revelations that White House intern Monica Lewinsky had oral sex with Clinton in the Oval Office leading him to declare famously on TV on January 26, 1998, "I did not have sexual relations with that woman, Miss Lewinsky." The scandal led to impeachment by the House for perjury, for lying about the affair under oath. He was acquitted in the Senate with 55 senators voting Not Guilty to 45 senators voting Guilty (falling 22 votes short of the two-thirds necessary to convict).
Most of the biographical information for all 20 politicians is from Wikipedia.
