Last year was a busy one for Hank Bargine, a freelance TV-news cameraman based in Colorado. The networks kept calling as the presidential candidates crisscrossed the country on the campaign trail. Bargine worked and traveled constantly, shooting rallies and other political events.

Now? Things are as slow as Bargine can remember in his 20 years as a news photographer. Bargine estimates he’s worked about 20 percent as much as he did last year. And he has no doubt what, or who, is responsible. “The Trump factor,” he calls it.

As in: The cable networks, in particular, have devoted so much time and attention to President Trump in his first six months in office that they have little time or interest in covering much else. Cable news has been so packed with Trump — wherever he might be, whatever’s he’s doing — that stories far afield from Washington don’t make the cut.

The current Trump-centric focus is an extension of the 2016 campaign, when the cable networks drew criticism for devoting disproportionate amounts of airtime to Trump, the candidate, at the expense of his political rivals. The networks — addicted to the improved ratings that all things Trump brought their way — seemingly couldn’t help themselves. “These are very good times for us, and the money is following,” CNN President Jeff Zucker said in February.

If anything, 2017 has been more of the same — much more.

The three leading cable news networks rarely discuss any topic other than Trump during prime-time hours, their highest-rated period of the day. Trump is the focus during daytime hours, too, when cable news actually tends to report some news, rather than merely talking about it.

Over the course of 24 hours on Monday (to take one midsummer day at random), CNN reported and discussed almost nothing else but Trump. A few unrelated topics slipped in — the kidnapping of a British model, a controversial memo written by a Google employee, some news about Syria. But Trump and Trump-related issues dominated, from his declining poll numbers to his Twitter attacks on Sen. Richard Blumenthal (D-Conn.) to the latest on the Russia investigation. At 9 p.m., the network ran a special one-hour report: “Why Trump Won.”

And this was all before Trump promised an apocalyptic rain of “fire and fury” on North Korea on Tuesday, a remark that naturally inspired another cycle of discussion and reporting.

The president, of course, is almost always the world’s leading newsmaker, so it’s no surprise that he commands inordinate attention, both on the air and in other media. And Trump’s administration has been unusual, to say the least. “We’re reflecting the biggest story of our lifetime,” said Zucker in an interview on Thursday.

But cable’s reliance on Trump is as much a programming strategy as a reflection of the news of the moment. Zucker acknowledges that the audience’s response to all the Trump news on cable validates the approach. Only a few years ago, “writers wrote that cable news was irrelevant, that it was being overtaken by the Internet,” he said. “The fact is, cable news has never been more relevant or more successful than it has been for the last two years.”

In fact, Trump has driven the cable news networks to the highest audience totals in their history, exceeding even last year’s campaign, which was the highest-rated ever. This is especially noteworthy because cable ratings are cyclical, and tend to decline after an election year.

So far in 2017, Fox News’s ­average audience has increased ­18 percent, to 1.54 million viewers per hour, according to Nielsen Media Research. CNN has seen an 8 percent rise, to 784,000, although its prime-time programs have lost 15 percent of their audience compared with this point in 2016 (CNN says prime-time comparisons with last year are skewed by the number of exclusive debates and town halls it aired last year).

The biggest winner has been MSNBC, traditionally cable news’s No. 3, but now second (849,000) after a 55 percent surge this year. MSNBC’s leading personality, Rachel Maddow, has become the most-watched figure on cable news, thanks largely to her nightly critiques of the president and his administration.

“We try to squeeze in major stories that need to be told,” MSNBC President Phil Griffin said Thursday, “but there is one story that is dominating.” Besides, he adds, “We don’t want to do 20 stories with drive-by reporting. [Cable news] is much better when it picks a few and goes deep, looking at it from all sides.”

The good news for cable news isn’t shared by people like Bargine, who rely on field assignments from a variety of news networks. Those assignments began drying up after Trump’s inauguration, he said, as his clients shifted to covering the White House almost full time. “There was one major story that consumed the networks from that day on: Trump,” he said. He added, “My phone stopped ringing.”

Bargine gets an amen from Gil Miller-Muro, who owns a business providing mobile satellite uplinks to news stations for live reports from distant locations. “The Trump effect,” he says, has hurt people in his field because many broadcast and cable news stories now originate from within locations that are already prewired — the White House, Capitol Hill, the Justice Department and the Pentagon — reducing the need for an uplink truck, he says.

“Every network is filled with hungry, creative journalists who want to dive in to different stories — about race, the economy, Wall Street,” he said. “But the things they get to cover are fewer and far between now” because of Trump’s dominance of the news agenda.

For Miller-Muro, the Trump effect is personal. Business has been so erratic this year that he’s decided to wind his down. Later this month, he’ll start a new management position at WRC, the NBC-owned station in Washington.