Television personality Sean Hannity, right, speaks as President Trump listens during a November rally in Cape Girardeau, Mo. (Jeff Roberson/AP)

President Trump often tries to move the American public through the sheer force of reiteration. At generous moments, it’s described as his genius at branding. But it’s probably more like that time on “Seinfeld” when George Constanza compares his dating strategy to a commercial jingle that gets stuck in your head.

You’ll therefore forgive Trump for expressing enthusiasm when it seemed like his most famous recent ditty — “The … witch hunt!” sung to the tune of the old “By Mennen” jingle — appeared to have caught on. A USA Today-Suffolk University poll suggests that 50 percent of the country views special counsel Robert S. Mueller III’s investigation as a witch hunt. Except that this is about equal, from a statistical standpoint, to those who say it isn’t. And except that the question asked not only whether it was a witch hunt, but also whether Trump’s been subjected to more investigations than most presidents. And except that there were several other red flags.

Regardless, a hum-able jingle is one thing. But it won’t catch on unless there’s real marketing muscle behind it, like constant television airtime that powers the product’s sales pitch. And for that, it seems, Trump can in this case thank his friends at Fox News.

Suffolk University’s poll includes a question asking people what news or opinion source they trust the most. Fox News is consistently the network that gets the most support in that regard because it’s consistently the network cited by at least half of Republicans. More than half of Democratic responses are divvied up between the broadcast networks and MSNBC, with a quarter of respondents pointing to CNN. Even CNN and MSNBC combined, in fact, are named as most trusted by a lower percentage of Democrats than the percentage of Republicans who say that about Fox.

(Philip Bump/The Washington Post)

(We noted last week that Fox’s audience isn’t as heavily Republican as you might think.)

Fox News covers Mueller less than its competitors. Since May 1, 2017, shortly before Mueller was appointed, Fox has mentioned Mueller about half as frequently as CNN and about a third as much as MSNBC. Here’s what that looks like by day between CNN and Fox News. More than three-quarters of days since then, Fox News has mentioned Mueller less than CNN.

(Philip Bump/The Washington Post)

When it does, the coverage isn’t always fawning. Fox News hosts such as Sean Hannity have been explicit about driving a narrative of distrust about Mueller and his investigation, claiming bias rooted in the earliest days of the Russia investigation.

There’s been a whole sprawling world theory, as demonstrated when you consider how often the networks have mentioned Peter Strzok, the former FBI agent who has been positioned by Trump and his defenders as the originator of the purportedly flawed investigation. Fox News has mentioned him five times as often as has CNN.

Bringing us back to that Suffolk poll. The pollsters asked respondents whether they thought Mueller’s probe would be fair and accurate. More than half said they had at least some trust that it would be — but more than half of Republicans said they had little or no trust it would be. Nearly two-thirds of those who said they most trusted Fox News held the same position.

(Philip Bump/The Washington Post)

In other words, Fox News viewers were significantly more likely to say that they had little or no trust in Mueller’s probe than Republicans overall. In other words, a better predictor of whether someone lacks confidence in Mueller is if they watch Fox News than if they are Republican.

Same holds in the other direction. Fox News viewers are significantly more likely to have a lot of confidence in Trump’s repeated denials that any collusion took place between his campaign and Russian actors.

(Philip Bump/The Washington Post)

The differences between Democratic viewers and CNN viewers on these questions are not similarly significant. (There weren’t enough people who most trusted MSNBC to pull them out separately.)

On other issues, Fox News viewers and Republicans are more in line. Like on a question from the Suffolk poll about whether Democrats were doing the right thing in pressing multiple investigations into Trump, his administration and his business.

(Philip Bump/The Washington Post)

Or the impeachment question, where only about half of Democrats thought the House should move forward.

(Philip Bump/The Washington Post)

On those questions, Republicans and Fox News viewers were broadly in line.

This ongoing question of how the energy flows between the Trump White House and Fox News remains unresolved, to the extent that the two are differentiable. But on questions of Mueller and Trump’s assertions that there was no collusion — something on which he’s insisted more than 200 times — it seems as though Fox News’s promotion is bearing more weight than Trump’s “witch hunt” jingle.