For 51 nights in 1973, millions of people flipped on their televisions at 8 p.m. Eastern time to tune into the prime-time political soap opera brought to their living rooms from Capitol Hill — President Richard M. Nixon’s Watergate impeachment hearings.

It was like “a kind of extended morality play,” as one of the nascent PBS’s news anchors described the network’s gavel-to-gavel coverage at the time. Viewers picked their heroes and villains in Watergate spies and insider White House witnesses, watching as the episodes of dramatic testimony on burglary and “dirty tricks” stretched well past midnight.

But while the public broadcaster’s experiment in uninterrupted evening impeachment coverage was a wild success then, PBS won’t be doing it the same way for President Trump’s impeachment hearings this week — a decision that has incensed some of broadcast journalism’s most veteran reporters.

On Friday, Bill Moyers, who worked for PBS during the Nixon era, and his colleague Michael Winship demanded in a New York Times full-page ad and in columns on Moyers’s website that PBS, “for the sake of the nation,” both broadcast the impeachment hearings live and replay them on prime-time television. PBS, the longtime journalists argued, could forgo its evening programs such as “Antiques Roadshow” as a “small price to pay for helping preserve the republic,” just as it famously did in 1973. The public hearings are set to begin Wednesday and are expected to be live-streamed by the major networks, but working Americans likely won’t get to watch them during the day, the journalists noted.

“This is a moment in American history where the arc of justice will either be bent forward or it will be bent backward,” Moyers, who also served as President Lyndon B. Johnson’s press secretary, told CNN’s Brian Stelter on Sunday. “So everyone who wants to see it should have the chance to see the whole story.”

PBS said Friday the network will broadcast live during the day but will then offer the hearings on-demand on its digital platforms. PBS WORLD, a digital channel carried by 157 public television stations representing about 64 percent of U.S. TV households, will also replay the hearings during prime time, ensuring that “Americans have access to the replay of the hearings when and how they want to view them,” a spokeswoman told The Washington Post.

Moyers and Winship, however, were dissatisfied with the network’s plan, saying that without the prime-time rebroadcast on its most accessible channel, PBS’s efforts are not enough.

“How in the world — no pun intended — does it serve democracy to hide the hearings from people who come home from work to see them but don’t have cable, satellite, and Internet access?” Moyers and Winship, a former PBS writer and now a senior writing fellow at Common Dreams, wrote in a column responding to PBS’s announcement. “If PBS were truly an alternative to corporate networks, it would repeat the hearings in prime time for the mass audience. Period.”

Stretching back to President Andrew Johnson, impeachment hearings have always been a public spectacle. For Johnson’s impeachment trial, the U.S. Senate issued admission tickets as if it were a county fair. For President Bill Clinton’s hearings, salacious details traversed the Internet and trickled across cable news by the hour. But for Nixon, there was something new and wholly unfamiliar to American television viewers at the time: the opportunity to watch the hearings in their unfiltered entirety, from the couch with a bowl of popcorn — thanks to the young and emerging PBS.

“The hearings showed Americans that democracy can work because they saw it at work,” Moyers and Winship wrote. “The coverage catapulted a fledgling PBS into the national consciousness. We know because we were there.”

To even put on the wall-to-wall coverage was a risk. At the time, Nixon had it out for PBS, having recently vetoed a public-broadcasting funding bill that had many in the industry fearing he was bent on killing the government-funded news outlets altogether. Johnson had only just signed the Public Broadcasting Act a few years earlier. During the Nixon administration’s tirades against “Eastern liberal” public broadcasters, Moyers, in fact, saw his own program, “Bill Moyers’ Journal,” temporarily kicked off the air after a purge of numerous public affairs programs.

But James Karayn, head of the now-defunct National Public Affairs Center for Television, insisted to superiors that airing the Nixon impeachment hearings was worth risking the administration’s wrath and gaining the public’s confidence. And finally, in the spring of 1973, his superiors and just over half of PBS member stations agreed. “We are doing this as an experiment,” news anchor Jim Lehrer said at the end of the first day’s hearings that May, “temporarily abandoning our ability to edit to give you the whole story, however many hours it may take.”

From May to November 1973, the hearings aired for nearly 250 hours, which initially presented a funding challenge, according to the American Archive of Public Broadcasting.

But as Karayn predicted, it was worth it, turning the Watergate hearings into a ratings and viewership boon for PBS. People became obsessed — “caught up in all this to a degree that might seem unlikely to anyone who didn’t experience it,” Charles McDowell Jr., a longtime Virginia-based journalist, said in a 1983 PBS documentary about the Watergate hearings. “Day after day, week after week, we watched the drama play out in one disclosure one after another."

Anchor Robert MacNeil likened the evening television broadcast to a Shakespearean tale, as “the forces hostile to the king are rising on all sides,” and as “messenger after messenger rushes in with bad news.”

“But the decisive battle is still some scenes away, and we don’t yet know if this is a tragedy we are witnessing,” MacNeil said, according to the American Archive of Public Broadcasting.

One viewer, June Wilson, wrote to PBS saying that since she began watching the evening rebroadcast, she had not even had time to finish sewing projects after work.

“Since I work during the day I would be hard pressed to keep up with the testimony and nuances which undeniably show themselves in such a hearing,” she wrote. “Thus I arrive red-eyed and sleepy to work and don’t care."

Of course, as the summer wore on, viewers began to lose interest, and when the Senate Watergate Committee announced it was extending the hearings again in October, most PBS stations voted against continuing the gavel-to-gavel coverage, the American Archive of Public Broadcasting reported.

But a PBS spokesman said at the time, “I think the whole public reaction simply indicates that if we can possibly do it, we are obligated to provide the coverage.”

After PBS announced Friday that it would replay the impeachment hearings live broadcast on PBS WORLD and digital platforms, Moyers and Winship were flabbergasted as to why the network did not feel the same obligation now as it did then.

The spokeswoman for PBS told The Post, as well as Moyers and Winship, that “we live in a vastly different media universe than we did 45-plus years ago,” one that is now an “on-demand world.”

But the journalists argued the new media universe should not matter.

“By thus failing to offer an alternative to the profit-hungry commercial networks in prime time, we suspect most Americans will miss the hearings in the day and at night many will go to their respective partisan corners on MSNBC or FOX,” they wrote.