Ben Smith on the Cable News Networks: “They appeared to be in terminal decline before Donald Trump turned it into the greatest, most terrifying show on earth.”

If Twitter is the twisted heart of America’s public conversation, cable news is its aorta, carrying fear and anger, as the rapper and activist Killer Mike put it last week, into the body politic. The coronavirus pandemic and the new urban crisis have made it impossible to look away, and journalists have at times become targets for the police. In this extraordinary news moment, the primacy of this supposedly dying medium has never been clearer, its ratings higher than ever.

But behind the scenes, chaos and uncertainty are also reaching record highs. I spent last week speaking to homebound executives, producers and on-air talent at the three cable news networks and found them wrestling in wildly different ways with an exceptional news moment that does not fit into cable’s familiar boxes: the coronavirus story, the economic crisis, and the protests and fires in the streets of American cities.

The power, and the stress, are clearest at Fox News, by far the most-watched American news channel but one that has been in a rolling corporate crisis since its founder, Roger Ailes, was forced to resign amid sexual harassment allegations almost four years ago. Fox News now occupies a strange position in a shrunken Fox Corporation, whose chairman, Lachlan Murdoch, has sought to pull off an acrobatic feat: collect the abundant profits from the channel while skirting the blame for its missteps in the early days of the pandemic. . . .

MSNBC has been scrambling in a different way. The channel thrived from 2017 until earlier this year, lifted by its nonstop coverage of the Trump-Russia story and the story’s denouement in impeachment. It signed up former spies and prosecutors as contributors, and dangled the hope that Robert Mueller would end Mr. Trump’s presidency. But the Russia show came to a disappointing conclusion for its audience with Mr. Trump’s acquittal on Feb. 5, and ratings plummeted. . . .

MSNBC’s audience numbers did rebound with the coronavirus story, but the network’s DNA is politics, and Covid-19 is not at its heart a political story. Rachel Maddow, the network’s star, saw her audience in the 25-to-54 demographic, the one most prized by advertisers, fall below CNN’s Chris Cuomo for the first time. . . .

CNN once positioned itself between MSNBC and Fox on the political spectrum. But during Mr. Trump’s tenure, the network concluded that there was no profitable middle ground with a president who seeks confrontation with the media. The channel adopted an increasingly political focus, hosting dozens of Democratic primary town halls and debates. It also competes more directly with MSNBC than ever before for audience, offering Don Lemon and Mr. Cuomo as a more emotional, less cerebral alternative to Chris Hayes and Ms. Maddow. . . .

CNN remains a network identified with and defined by one man, Jeff Zucker, the chairman for news and sports at WarnerMedia as well as CNN’s president since 2013. He runs the 9 a.m. news calls, and his refrain has been to stay on the coronavirus. His fingerprints are all over the programming, and CNN’s confidence tackling the dangerous, physical scrum of breaking news paid off in its vivid coverage of Mr. Floyd’s death and the aftermath. He has been telling his staff for months that the pandemic is the central story, and he told me he anticipated it to dominate the rest of the year. . . .

Lurking in the background for all the networks, though, is the question: How long can this last? Cable news appeared, like much of linear television, to be in terminal decline before Donald Trump turned it into the greatest, most terrifying show on earth.

CNN, the original cable news network that turns 40 on Monday, is at the heart of that question. Its commitment to on-the-scene reporting produced the riveting coverage, and arrest, of its correspondent Omar Jimenez on Friday morning. Its iconic status drew protesters on Friday night to its Atlanta headquarters, where they vandalized its globally recognized logo and defaced the building, putting CNN where it has often found itself in the Zucker years — right in the center of the story.

“They are telling our stories, and you are disgracing their building,” Atlanta’s mayor, Keisha Lance Bottoms, told demonstrators. But Killer Mike, whose real name is Michael Render, spoke for a nation exhausted by the endless adrenaline shots of news and conflict when he told the network to “stop feeding fear and anger every day. Stop making people feel so fearful. Give them hope.”