“At times it seems that being a Luddite may be the safest way to do serious national security reporting in a climate where there appears to be an intensifying war on serious journalism,” Mr. Scahill wrote in an e-mail.

Noah Shachtman, editor of Wired.com’s Danger Room blog, said that sources had told him to stay away in the recent climate of leak prosecutions.

“There’s one source I have to run into ‘by accident’ at some public function who before I could just contact directly,” Mr. Shachtman said…

“It’s so bad that there’s a gallows humor that has sort of emerged out of this,” Mr. Meyer said. “You see journalists at parties, and you joke about ‘How is the investigation going?’ ” People just assume they’re being investigated, and it’s not a good feeling.”

He said that he was “highly skeptical” of President Obama’s announcement. “One would think he would have done that months or years ago when these investigations were authorized.