Even that wouldn’t protect him from state charges. New York is certainly going after him. Maybe Florida too?

In a perfect world, Trump would resign after losing, and then Pence would not pardon him. Pence’s wife despises Trump, she might talk him out of a pardon. And if Pence had a very short Presidency, might he not want to look out for his own legacy?

Edit: even better, Pence could listen to his wife AND keep his promise to Trump. He could pardon him for one very specific thing but leave federal prosecutors a loophole they could drive a truck through.