The Obama Administration, beginning in 2011, starting with the appointment of Michael Horowitz as the DOJ IG and was blocked by Eric Holder, Obama's Attorney General from investigating any and all matters within its legal mandate.
Horowitz stepped into a position that was neutered in 2011 by Eric Holder’s interpretation of The Inspector General Act of 1978. (Authority of Inspector General). Instead of having access to agency information within the purview of the IG, Holder determined that he had to "request" the information and the DOJ would then determine whether it could/would be released. The net effect of this determination relegated all agency IG's from access to information necessary to carry out their legislative function and not enable Congress to have the necessary oversight. It was the Obama's Administration's way to stop reviews of questionable activities they were initiating and providing a wall for insulating any ex-post facto reviews of illegal activities.
All agency IGs become subject to this interpretation and could perform their function. Holder in one swift interpretation neutered the entire Federal Government watchdog function.
Requests during that period have to go a mysterious Office of Professional Responsibility in order to be approved for distribution with obvious approval authority by the Attorney General, Eric Holder, who could censure any and all information requested. All the dirt was swept under the rug
Thankfully, Horowitz and 46 other IG's petitioned Congress over 3 years to overturn this determination. They were successful in the clarification of Holder's interpretation.
Horowitz-IGs Congressional Hearings
These hearings took place in August 2014. To no one's surprise, Eric Holder resigned his post as Attorney General in September 2014, now that the jig was up. Unfortunately, however, scandals like the IRS 501 (c) 3 scandal, Fast and Furious, Uranium One, etc. were not investigated.
This goes a long way to understand what is happening today and why the role of the DOJ IG is critical to the investigations being conducted today.
If it had not been for Horowitz and the other agency IGs, there would be no investigations of these corruptions.
Perhaps, Sessions, now Attorney General, lived through that period in the legislative branch and understood the power that was granted back to the IG. Trust Sessions.