During the Watergate investigation, I contributed to an unprecedented history of presidential misconduct that the impeachment inquiry of the House Committee on the Judiciary requested in 1974. Now, 45 years later, I’ve edited an expanded version, covering all U.S. presidencies through Barack Obama’s. Looking over that 230-year span, what I’m forced to conclude is deeply troubling: Since the early 1970s, the behavior of American presidents has worsened in alarming ways.

Until then, executive branch malfeasance followed what we might think of as normal human misbehavior: the search for easy money, attempts to escape responsibility and the subversion of existing law for personal gain. Only occasionally, and then without major threat to the public welfare, did administration officials thumb their noses at the law and engage in flagrantly illegal acts.

That changed decisively in the 1970s.

With the presidency of Richard M. Nixon, criminal acts were engineered and implemented directly from the White House. Then, during Ronald Reagan’s administration, a shadow government composed of administration officials acting outside normal channels and without legal authorization seized control of aspects of U.S. foreign policy.

Today, the Trump White House has allegedly engaged in what looks like a breathtaking combination of both Oval Office complicity and shadow government operations. These two kinds of illicit executive action seem to have been brought together to drive U.S. relations with other foreign powers. This sort of criminal behavior has never before so permeated a presidency or so deeply threatened American governance.