All prosecutorial decisions are political. Not necessarily in the partisan sense, but rather, in the sense the prosecutor balances the seriousness of the conduct involved, with the purpose of the laws that might be violated, and his job is to act in the best interest of the United States government.
The leak of Valerie Plame Wilson's covert identity, if it was part of a plan to discredit her husband's report on his trip to Niger, is directly related to issues of "national security."....
But national security is a very gray area. Was the Bush/Cheney White House operating in the best interest of the country, or did they have a private agenda (oil fields in Iraq)? Did Cheney, Karl Rove, and Scooter Libby believe they had national security reasons to discredit Wilson's claims, and act accordingly? This is an area where there is no law, and it compounds the assessment of the actions of those involved.
Steve Gilliard and Whiskey Bar to our rescue.