There is a pattern to these things. FOX News journalists are treated as un-journalists. Targeting them is okay regardless of their actual politics because they part of the “enemy camp”.
Before the Justice Department was secretly obtaining phone records of Associated Press reporters, the Obama administration was investigating a Fox News journalist.
According to the Post, the Justice Department went further in investigating Rosen than they did with AP reporters. They obtained his security badge access records at the State Department, looked at records of his calls with a specific State Department adviser and even went through his personal e-mails.
Email seizures go beyond phone records. And the nature of the leak appears to have been less dangerous since it involved saying what everyone already knew. That North Korea was going to conduct more nuclear tests. I knew it without any secret leak access.
It does not appear that Rosen received any classified information. Rather he received an informed opinion from someone with access to classified information, which is not at all the same thing and happens routinely in Washington D.C.
The real question is why Rosen was being targeted and the likely answer is because of his affiliation and because he was reporting inconvenient things.