This thing specifically remind me of the corruption the USSR / Russia has struggled with for decades.
The corrupt politicians staff the justice system with people who rule in favor of the corrupt politicians and their cronies. If you investigate the people / party that appointed you, you’re out.
The US has never gone full-Russia, but Trump wants to do that. Previously the rich and powerful have simply been able to get a leg up because they were able to outspend the justice dept. Under Trump, the justice team will be on the same team as the people they should be prosecuting.