Sometimes, President Trump gets an obsession. Something works its way into his patter and sits there for weeks or months, seeping out into his tweets and into his speeches. It can be a tagline or an insult; it can be a story or number. If you’ve been paying even partial attention to American politics in the past five years, I don’t even have to mention any of them. You can rattle off a half-dozen without blinking.

One of the recent entries into this canon is a drug called chloroquine. Trump has become convinced that the treatment for malaria also can offer substantial relief for covid-19, the disease caused by the novel coronavirus, which has infected hundreds of thousands of Americans. Doctors and medical experts are broadly skeptical of the drug’s efficacy, but Trump has nonetheless hyped it repeatedly at news briefings and in interviews.

His interviews have mostly been on Fox News, where Trump probably first saw coverage of the drug. This would not be the first time that Trump seized on something he’d seen on Fox and made it part of his standard verbiage, but this may be one of the most obvious instances. Closed-captioning data from the Internet Archive processed by the GDELT Project shows that four of the six television shows that have mentioned chloroquine the most in the past month are Fox News programs.

(The charts in this article show any program that constituted at least 2 percent of the mentions of the term at issue.)

Laura Ingraham, host of “The Ingraham Angle,” has even visited the White House to tout a related medication, hydroxychloroquine. About a third of the time that that has been mentioned on cable news, it’s been on Ingraham’s show or on Sean Hannity’s. Each has mentioned it twice as often as any other show.

The context of those mentions matters. Ingraham’s mentions of chloroquine and hydroxychloroquine have largely been to advocate for them as treatments for covid-19. Mentions of chloroquine on other networks have been stories about Trump’s promotion of the medication or adjudication of Trump’s claims about them.

Why Ingraham in particular is so invested in the issue is a subject left for another day. But, again, we’ve seen this Fox-to-Trump pipeline work its magic repeatedly.

Consider Trump’s brief insistence on identifying the coronavirus as a “Chinese virus” last month, an insistence that overlapped with a social-media push to link the virus more frequently to China. Since the beginning of the year, eight of the 10 shows using the term “Chinese virus” the most, according to GDELT’s estimates, were Fox News shows.

Those numbers are a bit skewed, though, since many of the non-Fox mentions came before Feb. 11, when the World Health Organization named the virus. From Feb. 12 on, the top seven shows to use the term were all on Fox News. The non-Fox shows were, again, mostly commenting on Trump’s use of the term.

Over and over, Trump echoes the language used on Fox News and Fox News echoes the language used by Trump.

Since Trump took office in 2017, the shows that were most likely to use the term “illegals” to describe immigrants in the country without documentation were all Fox News shows.

Over the course of investigation and impeachment of Trump centered on his interactions with Ukraine, Fox News shows were more likely to mention Hunter Biden, son of the former vice president. Trump’s defense in the impeachment was predicated on unsupported allegations that the younger Biden had violated the law. During that period, Hannity in particular spent a great deal of time focusing on Hunter Biden.

This is a pattern for Hannity. Trump’s focus on former FBI agent Peter Strzok as a bad actor in the launch of the investigation into Russian interference in the 2016 election came up on Hannity’s program more than any other. It also came up on Fox News far more than on any other network.

Hannity and Ingraham were more likely than other programs to use the term “deep state” — the nebulously defined group Trump blames for a variety of ills — since the beginning of last year.

“Witch hunt”? Most common on Hannity’s program.

“Hoax”? Most common on Hannity’s program.

To put a fine point on it, Fox News and Sean Hannity in particular are often either the source of or megaphones for the issues and arguments that Trump embraces as president. Over and over, the cable network that spends the most time talking like Trump is Fox News, even when it comes to a term such as “fake news,” which no program has mentioned more often than Hannity’s.

The show most likely to use the word “irony” was Tucker Carlson’s.