President Biden himself should stay out of it, and rightly seems intent on doing so. His Justice Department, however, can’t and shouldn’t. Previous presidents and previous prosecutors gave former presidents a break for their misdeeds: President Gerald Ford pardoned Richard M. Nixon; independent counsel Robert W. Ray (Kenneth W. Starr’s successor) reached a plea deal with President Bill Clinton on Clinton’s last day in office.

Trump deserves no such grace. His wrongs are far too many to ignore. His demonstrated contempt for the constitutional and legal order is simply too great. That was clear enough before Trump’s repellent and possibly criminal efforts to overturn the election results, for which he was duly impeached. Now, an effort to hold Trump to account in the criminal justice system is essential and unavoidable.

To deal with Trump, and to do so fairly, Attorney General-designate Merrick Garland, once confirmed, will need to use the mechanism of a special counsel. Indeed, given the astonishing breadth of Trump’s wrongdoing, Garland may need to appoint more than one to get the job done swiftly and thoroughly. What follows is a guide to how and why the case or cases, United States v. Donald John Trump, must be pursued.