Jeff Sessions was Trump’s Elliot Richardson, and Archibald Cox was his Robert Mueller. Trump bungled badly by choosing Sessions as AG. I think it put him in a very precarious position. Trump’s advantage was that he was completely innocent, and yes - he DID fight.
Who Trump should have learned from is Obama. Obama made sure he had true fellow-travelers as his AGs. He even made sure they were black and “down for the struggle.” Of course, they were political and biased as hell, but with Holder-Lynch, Obama was absolutely safe from any attacks from within the DOJ/FBI establishment.
Rudy or the Fat Guy would have been better choices for AG.
Trump won because he was a DC outsider. The down side of that election scenario is that you get someone in the White House who has no Beltway-savvy people in his inner circle.