2003: In an effort to discredit U.S. Ambassador Joseph C. Wilson, who had written an article critical of the 2003 invasion of Iraq, Washington Post columnist Robert Novak reveals that Wilson's wife Valerie Plame (pictured here in 2007) is a CIA covert operative. The column effectively ended Plame's career with the CIA and she later formally resigned in December 2005. The resulting scandal also led to a criminal investigation over the leak, although no one was ever charged for the leak itself. Scooter Libby, Vice President Dick Cheney's chief of staff, was eventually convicted of lying to investigators in connection with the case, but his prison sentence was ultimately commuted by President George W. Bush.