Robert Novak, the "principled" journalist who released the name of a CIA agent to the public. The CIA agent is the wife of former US Ambassador Joseph Wilson who researched and disagreed there was any evidence of the sale of Nigerian uranium ore to Iraq before the war. Wilson charged that someone in the Bush administration (maybe Rove) leaked his wife's name to Novak because Wilson's report to the CIA wasn't what they wanted to hear.
For me, Novak's standing as a journalist of credibility is quite wobbly. However, there are two sides of the story.
Both sides speak, including Novak's weak rationales (MHO):
http://search.looksmart.com/p/browse/us1/us317916/us53358/us155877/us10176375/us10174299/us10201102/
Sherwood