Smith's federal criminal cases against Trump were upended by the election, as the Justice Department's longstanding policy is that sitting presidents can't be charged with crimes.
The Darkest Brandon move would be to remove the DOJ policy on not investigating sitting Presidents. Many of these cases were clearly not under Presidential Immunity, and some weren't even done while Trump was President. That should have consequences regardless of getting the job back or not.
I still don't understand how this is an official DOJ policy. I always see it referenced as a DOJ memo from the 70s. Who gives a shit about memos? This is supposed to be a country of laws, not 50 year old memos.
But yeah, would love Garland to issue a new memo overturning that policy. Let Trump's first official act be to overturn an existing policy to prevent him from being investigated. Not saying he would even hesitate to do it, just saying I'd like to make it an explicit step he has to take.
That's government for you. If the 50 year old memo is the only thing that talks about it, then that's the basis forever. There's so much stuff like this that there's an actual legal term for ignoring it: Desuetude. But that's usually for things much, much older than that, and they would have been actively ignored for almost as long.