Veteran of Nixon's 'Saturday night massacre': Trump's actions remind me 'eerily' of the Watergate days
Ruckelshaus wrote that ongoing controversy over the Russia investigation could have been put to rest by President Donald Trump "revealing all he knew and instructing his staff to do the same."
He noted that former president Richard Nixon could have done the same following the 1972 Watergate burglary.
"But President Trump hasn't done that, even though he has consistently asserted his complete innocence," Ruckelshaus said. "Why not lay it all out for the public to judge for itself? Are we headed for another long national nightmare? For the sake of the country, I hope not."
Trump has grown visibly frustrated with the Russia investigation, and in recent days has publicly derided Attorney General Jeff Sessions and said he would not have nominated him for the position had he known Sessions would recuse himself from the probe.
Top Trump administration officials have also publicly questioned the integrity of special counsel Robert Mueller and the team of investigators he has hired, some of whom have donated to Democrats in the past. But Mueller has a sterling reputation and is conducting a fair investigation, Ruckelshaus said.
"He is universally and justifiably admired and should be supported in his work," he said.
Trump appears to be heading towards some of the same pitfalls that led to Nixon's resignation 10 months after the "Saturday night massacre," during which Ruckelshaus and former Attorney General Elliot Richardson resigned and Cox was fired, Ruckelshaus said.
He added that during the Watergate scandal he had been convinced Nixon would not call for Cox's firing, believing that "he'll never do it. The American people won't tolerate it." And while he was wrong about the former point, he said he was correct about the latter.
The following 10 months resulted in a collapse of Congressional support, impeachment hearings, a Supreme Court-ordered release of tapes that revealed Nixon and his aides had plotted a cover-up, and ultimately, Nixon's resignation.
"If the president fires [Mueller], as he is reportedly contemplating doing, the result might very well be the same as what President Nixon faced," Ruckelshaus said.
"Mr. President, don't worry whether you have the power to pardon yourself. But do consider the wisdom of firing the man charged by your own deputy attorney general with investigating Russian intervention into your election."