President Donald Trump pushed Attorney General Jeff Sessions to resign on Wednesday. Matthew Whitaker, Sessions' chief of staff, who has expressed hostility to Special Counsel Robert Mueller's inquiry, will step in as acting attorney general and, according to reports, take over supervision of the investigation.
The president has the right to replace his Cabinet officials. After all, it's not unusual, as Trump said during his news conference earlier Wednesday, to have some turnover after an election.
But the head of the executive branch does not have the right to attempt to end investigations of himself, his campaign and his administration. Those kinds of actions are called abuse of power and obstruction of justice.
For the moment, there's no sign that Trump is attempting either a rapid or a slow-motion re-enactment of the so-called Saturday Night Massacre of 1973, when Richard Nixon ordered the firing of a special prosecutor, which contributed to the chain of events that ultimately led to the president's downfall.
Nor do we know how the American people in general or Republicans in Congress in particular would react to such a move by Trump. Several Republican senators have repeatedly warned him not to try; on the other hand, they have refrained from taking pre-emptive actions to make it impossible.
The appropriate action at this point would be for both Trump and the acting attorney general to make clear statements that the investigation will continue without interference.
It would also be appropriate for Judiciary Committee Chairman Chuck Grassley and other Senate Republicans to make public declarations of their respect for the office of the special counsel. They should indicate that they will require any new nominee for attorney general to make the same no-interference pledge that the committee demanded of Elliot Richardson when he was nominated for the job in 1973. It's promising that Republican Sens. Lamar Alexander and Jeff Flake, and Sen.-elect Mitt Romney all spoke Wednesday about the importance of allowing an investigation to go forward. Sen. Susan Collins of Maine also weighed in.
Whether Senate Republicans fulfill that responsibility or not, Nixon's example should make it clear to Trump that any actions he takes to subvert the investigation are likely to backfire.