These excerpts from lectures by Barton Gellman, a Pulitzer Prize-winning Washington Post journalist, are well worth a read. He discusses the relationship between national security and a journalists' adversarial role, as well as how he goes about writing a story on classified information.

Gems: 

There is nothing anomalous here. I’m a projects reporter, and now my project is the weapons hunt. Nearly everything I want to know, and much of what I write, is classified. One day my adopted survey team seized a suspicious document, handwritten in Arabic and illustrated with sketches of laboratory glass. The document turned out to be a high school science exercise. The survey team’s report was classified. The school-book exercise was appended to that report—which means that some Iraqi teenager’s description of Boyle’s Law is a classified U.S. government secret. A qualified authority made a binding judgment that disclosure of this text would do “serious damage to national security.” So don’t ask me about the relationship between the pressure and volume of a gas held at constant temperature. I’d tell you, but I’d have to kill you.

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What happens when government conceals from us its deeds on behalf of our defense? With stakes of life and death, it is easy to see the vital need to deny advantage to an enemy. But life-and-death stakes give equal urgency to the project of holding our leaders accountable for their use of power. If we are sovereign, we rule those who rule us. Secrecy corrodes self-government, just as it strengthens self-defense. Both interests reach peak importance in time of war.