Opinion | I Worked at CNN and Reported on Tucker Carlson. He Was Never Invincible.

Monday’s purge of Tucker Carlson, from Fox News, and Don Lemon, from CNN, confirmed a belief that has been gnawing at me for years: We think about cable news all wrong.

The Friday episode of “Tucker Carlson Tonight” that turned out to be his last drew only about 2.6 million viewers — a measly 1 percent of the American adult population. But on Monday, the news of his firing was one of the top stories in the country. That’s because the power of cable news is in its reach and repetition, not its ratings.

I learned this during my nearly nine years at CNN, where I anchored a weekly program about the media and reported on Mr. Carlson’s radicalization. The people who tuned in to his show at 8 o’clock sharp were only a subset of his total audience. When you count all the people who saw him on a TV at a bar or in an airport and all the people who watched a clip on the internet or heard radio talk-show hosts quote him, he had a monthly audience of surely tens of millions.

Now multiply that reach by the dozens of other hosts on Fox News, and you can start to see the true influence of Rupert Murdoch’s media empire. Nielsen has a little-known metric for this, called cumulative viewership, and according to that measure, Fox News attracted more than 63 million viewers during the first three months of this year. Fox execs have pooh-poohed the cume data point, perhaps because the figure is bigger for CNN, closer to 68 million for the first quarter. But these metrics don’t fully account for the full digital reach of stars like Carlson and Lemon, either.

That’s why I dismiss predictions — fashionable, even at some of these networks — that cable news is doomed to irrelevancy. Do the math: CNN has seen recent declines but still expects to make $900 million in profit this year. Fox News doubles that. The endless sea of streaming content is stiff competition, but as long as there are 20 or 30 climactic days a year that make people want to reach for the remote and watch a live news event, cable news will be there for them.

The networks may be more influential than ever before, but they are definitely more polarized. CNN and Fox News make money the same way, largely through subscriber fees and ad sales, and they are frequently lumped together on cable channel lineups. I sometimes lumped them together myself, staring at the ratings spreadsheets and comparing the two channels as if they competed for the same slice of audience. But they don’t. And though Mr. Carlson and Mr. Lemon were both fired amid accusations that they had fostered hostile work environments, the two hosts existed in wholly different media universes.

Fox News, despite having a newsroom with reporters and editors, is primarily a conservative entertainment operation and a Republican Party organ. The news doesn’t come first or even second at Fox, and the reporters there know it. (Correspondents there called me and griped about Mr. Carlson’s conspiracy-laden broadcasts and their own limited airtime and inability to correct his alternative “facts.”) CNN, though it makes some attempts to be entertaining, is primarily a news-gathering engine, with correspondents and bureaus around the world that it maintains at great expense.

That difference has huge implications. Mr. Lemon’s reach made him a celebrity. Mr. Carlson’s reach made him an unelected leader of the Republican Party, someone the House speaker, Kevin McCarthy, had to propitiate. An entire ecosystem of far-right sites and social networks eagerly waited to promote Mr. Carlson’s episodes each night. That power can’t be measured, but it’s the key to understanding cable news’s sway.

Mr. Carlson repeated a story of good versus evil, full of conspiratorial and xenophobic rhetoric, every single weeknight. His repetition was his superpower, indoctrinating his fans and inoculating them against the truth. Bruce Bartlett, who served in the administrations of Ronald Reagan and George H.W. Bush, has called Mr. Murdoch’s machine the “Fox brainwashing operation” rather than Fox News. Mr. Lemon called it the “Fox propaganda network” because he didn’t think it was accurate to call it news anymore. Dominion Voting Systems’ legal X-ray of Fox News provided ample evidence to support him. In a darkly humorous way, the $787.5 million settlement is also a testament to cable news’s power — the power to destroy a company it sets its sights on.

This week has proved two things: the might of cable news and the fact that it is ultimately the networks, not the stars, that control it.

Mr. Carlson, according to my reporting and others’, thought his ratings made him invincible. Millions of people were buying what he was selling. But gravity has reasserted itself. Monday’s terminations show that there are limits, even at the extremes of cable news, and for all that the new media environment may have changed in the world, one of those limits is the same that you probably face at your job: If you get to be a big enough pain for your bosses, eventually you’re going to get canned.

But the cable show goes on. The audience insists on it. As word spread about Mr. Carlson on Monday, the ratings started to spike for a much smaller right-wing channel, Newsmax, which desperately wants to become the next Fox News. Within a few hours, Newsmax at one point had more than triple the usual audience for its never-ending pro-G.O.P. talk show. The next battle in the cable news wars has just begun.

Brian Stelter, formerly a reporter at The Times and anchor at CNN, is the author of the forthcoming book “Network of Lies.”

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