This op-ed was originally published in The New York Times.

In the post-Watergate era, most Americans have taken for granted that a president would not fire an F.B.I. director investigating him, or replace an attorney general for insufficient loyalty to the president’s personal interests. Dangling a pardon before potential witnesses to influence their testimony? Unheard of.

Whatever one’s feelings about the end of the Mueller investigation, the Barr letter makes one thing clear: The guardrails that were established after Watergate against these types of abuses have been smashed. We still need to see the full Mueller report, but unless corrective steps are taken, Mr. Trump and Mr. Barr will have changed, perhaps profoundly, the shape of presidential power, and in troubling ways.

Read the full op-ed in The New York Times.