The indictment of former president Donald Trump has taken the country into uncharted territory. Yet the case bears considerable resemblance to the successful prosecution of Vice President Spiro Agnew in 1973.

Fifty years ago this spring, a team of young lawyers in the U.S. attorney’s office in Baltimore amassed evidence that Agnew took bribes in exchange for companies winning state engineering contracts in Maryland. Then, as now, observers recognized that the United States was entering an era of holding its most powerful political leaders accountable for legal wrongdoing. As The Washington Post Editorial Board wrote at the time, the test would be whether the Justice Department and the courts could “proceed as they would proceed with any other public official — rigorously, impartially and promptly.”

The system passed that test, and on Oct. 10, 1973, Agnew resigned and entered a nolo contendere plea that ensured he would avoid jail time.

It’s not surprising that Agnew’s political fall anticipates Trump’s legal problems. After all, one can trace the popularity of Trump’s combative political temperament and slashing populism back to Agnew’s long-forgotten career.

While their two cases are similar, one crucial difference exposes how much Republican politics and media have changed over the past half-century.

Agnew burst onto the national political scene in 1968 buoyed by the “backlash” vote against the civil rights, anti-Vietnam War and counterculture movements. The Maryland governor caught the eye of Pat Buchanan, an aide to Republican presidential front-runner Richard M. Nixon, in the aftermath of the Rev. Martin Luther King Jr.’s assassination. Riots broke out across America, and while the leaders of Baltimore’s Black community had tried to contain the violence, Agnew castigated them for not denouncing it in terms he found sufficiently emphatic.

Later that summer, Nixon chose Agnew — despite the governor having no national name recognition — to be his running mate. As vice president, Agnew launched a populist assault that has become all too familiar now, blazing a trail of speeches in 1969 and 1970 that went a long way toward altering the nation’s political landscape.