The Sinclair Broadcast Group is likely the most powerful media company most people hadn’t heard of — that is, until last week, when a viral video showed one way the company could carry out its agenda.

The video, from Deadspin’s Timothy Burke, shows local anchors around the country reciting the same scripted lines that Sinclair provided. They all say they are “concerned about the troubling trend of irresponsible, one-sided news stories plaguing our country.” It’s the local news version of Sean Hannity or Tucker Carlson complaining that the “mainstream media” is lying to Americans. But now it’s not just happening on one influential station; it’s an organized effort happening on hundreds of stations, all around the nation.

We put a lot of attention on cable news channels like Fox News and MSNBC. But over the past few years, Sinclair has accumulated almost 200 local stations in nearly 100 markets, with a not-so-secret mission to push conservative, pro-Trump messages.

And Pew data shows that while local news viewership is falling, local stations’ audience is still comparable to that of network news and significantly higher than that of cable news.

I’ve written quite a few data-driven stories tracking conservative media, but it’s been difficult to track Sinclair because it owns hundreds of local stations. Researchers Gregory Martin and Josh McCrain recently published a paper that showed Sinclair-owned stations focused more on national news, which tends to be more politically charged. But looking for nationwide trends of Sinclair coverage — and finding examples of these trends — has been exceedingly hard.

This is why the Deadspin video was so powerful: It shows exactly how a company that controls so many local media outlets can influence messaging.

This is how many stations Sinclair owns in your area

Select your state and media market and we’ll see whether Sinclair owns stations in your area. (Note: Alaska and Hawaii do not have any Sinclair stations.)

These promos are easy to see, but the real influence will be harder to spot

Had Tim Burke of Deadspin not put together that video, we probably wouldn’t be writing about this. After all, several weeks ago, CNN’s Brian Stelter wrote about Sinclair’s plan to force its anchors to read these anti-media promos — and it wasn’t quite as alarming as seeing it on video.

But Sinclair’s influence might not be so apparent going forward; it might be far more difficult to track. And even when we catch instances of Sinclair’s right-wing agenda, they might not look as haunting as when we see them edited together.

In fact, some of the most troubling trends in conservative media are not so much the things that are said on air. Rather, they are the things that are ignored. Whether it’s downplaying the president’s alleged affair with a porn actress or a crisis in Puerto Rico, modern conservative media doesn’t just shape our picture of the world with persuasion; rather, it also does it with omission.

Now, this doesn’t mean all reports from Sinclair stations are compromised. Already, several journalists working at Sinclair stations have tried to distance themselves from this action, and at least one station said it did not air the promo:

In response to the Sinclair message aired: "WMSN/FOX47 Madison did not air the Sinclair promotional announcement during our 9pm news this weekend. Rather, we stayed true to our commitment to provide our Madison area viewers local news, weather and sports of interest to them." pic.twitter.com/MdQ568cWrH — FOX 47 Madison (@fox47madison) April 2, 2018

Stunts like Sinclair’s make it harder for all journalists, including at Sinclair-owned stations, to do their jobs. At a time when trust in media is eroding, the Sinclair promo not only told viewers to trust media less because of partisan bias; it allows them to cry “fake news” at anything they disagree with.