If you're right, and Berger must be held to account, why do you suppose the investigation is taking so long? (BTW, I believe we have a two-tier system of law: one made for ordinary people and Republican politicians. And another for high-level Democrats, who are above the law and above mainstream media scrutiny.)
Perhaps his crimes are just part of a larger conspiracy and eventually five dozen people will stand convicted.
In the Watergate scandal, it was necessary to follow the money, since the underlings were mostly motivated by money.
This case might require more lengthy use of wiretaps. I recall the scene in the movie "Day of the Jackal" when the detective is asked how he knew whose phone to tap. The detective explained that he didn't know and therefor tapped all of their phones.
Sensible people might hesitate to support the Patriot Act, believing that it relieves investigators of having "probable cause" before being granted search powers.
This case might provide an example of just how powerful the government can be with so little restraint. Perhaps every member of Congress and every member of the previous administration has had his phone tapped since last October in order to find out what prompted this blatant violation of national security.
We are witnessing treason on a grand scale. It should be expected that there will be consequences on a grand scale.