We are a group of citizens united by our deep concern over threats to the integrity of American democracy and the rule of law. With the indictments announced on Monday, the investigation by special counsel Robert Mueller into Russian interference with the 2016 election is now entering a new and critical phase.

At the same time, a growing chorus of Republican and conservative voices has started calling for Mueller’s resignation on trumped-up grounds, a move that may be calculated to help justify dismissal of the special counsel and pardons for his targets.

In view of these events, we want to come forward and express our strong support for allowing the Mueller investigation to proceed without interference or obstruction. We would regard dismissal of the special counsel, or pardons issued preemptively to anyone targeted by his investigation, as a grave abuse of power that justifies initiation of impeachment proceedings.

We hereby call on House Speaker Ryan and Senate Majority Leader McConnell to make clear, both publicly and privately, that they support the Mueller investigation and regard any interference with that investigation, including dismissal of the special counsel or preemptive pardons of investigation targets, as completely unacceptable.