Yes, the corruption started long before Garland was appointed as AG. It goes back to when Obama was president. Remember Fast and Furious? No one was punished for that mess. The IRS targeting of conservatives? No one was punished for that, or all the lying to congress. Remember when all those emails were lost because of 8 hard drive failures on one IRS department in a course of about 2 months? The probability of that happening is almost 0. Lois Lerner left her job after lying repeatedly to congress but was never prosecuted. Obama had his "wingman" in the AG's office. How about Loretta Lynch telling Comey not to call the Hillary email investigation and investigation? Make no mistake, it was Obama who corrupted the DOJ, we are only dealing with that now. Trump let Comey and his clique survive and it just worked against him.
At this point, the DOJ is just a DNC operation. Almost 2 dozen whistleblowers have come forward to allege partisanship in the DOJ. It is completely ignored. Imagine what the DOJ will do with all its resources to protect itself from the possibility of a Republican president intent on cleaning out the corruption? The problem is too many Republicans do not realize the Democrats are fight a war - against them.