Cox’s dismissal was triggered by his demand for full access to White House recordings that ultimately revealed Nixon’s complicity in the cover-up of the Watergate break-in. Nixon wanted to provide just limited summaries of the tapes and allow only conservative Democratic Senator John Stennis of Mississippi to listen to the recordings to verify the summaries’ accuracy. When Cox rejected those terms, Nixon ordered Attorney General Elliot Richardson to fire him. Richardson famously resigned instead, as did his deputy William Ruckelshaus. Finally, Solicitor General Robert Bork—later Ronald Reagan’s rejected Supreme Court nominee—dropped the axe.

The shock over Nixon’s coup from above hardly dispelled all partisanship. Reagan, then the governor of California, and George H.W. Bush, then chairman of the Republican National Committee, both defended Cox’s firing by likening it to Harry Truman’s dismissal of General Douglas MacArthur for contradicting administration policy during the Korean War. “We cannot have a man in [the] executive branch who does not answer to the head of the executive branch,” Bush said. When Cox testified before the Senate Judiciary Committee shortly after his dismissal, GOP senators Strom Thurmond of South Carolina and Edward Gurney of Florida tried to paint him as a Democratic sympathizer biased against Nixon.

But many other voices rose in bipartisan outrage over Nixon’s assault on the investigation. Those began with Richardson himself, who explained his resignation in a lengthy press conference. “At stake in the final analysis is the very integrity of the governmental processes I came to the Department of Justice to help restore,” he said.

Powerful institutions outside of government swelled the chorus. In the 1972 presidential campaign, the AFL-CIO had tilted toward Nixon by conspicuously remaining neutral between him and Democratic nominee George McGovern. But after the Cox dismissal, its national convention unanimously called for Nixon’s impeachment. The American Bar Association convened an emergency meeting to condemn the firing and its president urged the courts and Congress “to repel the attacks which are presently being made on the … rule of law as we have known it.” The public deluged the White House and Congress with telegrams and phone calls in what one Watergate historian called “the greatest outpouring of electronic protest ever seen.”

Critically, several congressional Republicans added their voices. Moderate Maryland GOP Senator Charles Mathias declared that “it is not right for any institution to investigate or prosecute itself.” Arizona Senator Barry Goldwater, the former GOP presidential nominee, said Nixon’s credibility “had reached an all-time low” and he “may not be able to recover.” The backlash was so fierce that Nixon relented within days and released the tapes Cox had sought.