COVID-19 is officially "an epidemic," Fox News host Tucker Carlson began his Monday night monologue. "There's no denying that now."

But for Carlson's single most notable audience member, President Trump, there's plenty of denying it. Though rumored to be privately panicky, Trump has maintained a studied nonchalance in public, accusing the media of untoward hysteria, sharing claims that Democrats' response is "another attempt to impeach the president," and insisting the whole thing will be less consequential than the seasonal flu.

As Carlson continued his spiel Monday, he took an obligatory swipe at the left, but it quickly became obvious his real targets were further to the right. "People you trust, people you probably voted for, have spent weeks minimizing what is clearly a very serious problem. It's just partisan politics, they say. Calm down. In the end, this is just like the flu, and people die from that every year," Carlson said, all but quoting from Trump's Twitter feed.

"No doubt these people have good intentions as they say this," he went on. "But they're wrong. The Chinese coronavirus is a major event. It will affect your life. And by the way, it's definitely not just the flu." Carlson distinguished between calm and complacence, urging public honesty and action to slow the spread of the disease so our medical system is not overwhelmed with a critical mass of cases all developing at once.

Whether Carlson will get through to Trump remains to be seen. The bulk of his own network's messaging is working against him — that clip Trump shared branding coronavirus reactions as an attack on his presidency ran on Fox Business, Fox News' sister channel, at the same time Monday night as Carlson's show. Likewise, Fox & Friends host Pete Hegseth declared on air Sunday that "more [he] learn[s] about coronavirus, the less concerned" he becomes, and Greg Gutfield of The Five has similarly suggested press coverage of the virus is driven more by hatred of Trump than real interest in public health.

But Carlson has won Trump against long odds before. He reportedly talked the president down from war with Iran this past summer, countering the influence of more hawkish advisers like Secretary of State Mike Pompeo and then-National Security Adviser John Bolton. In January, Carlson again pushed back on more aggressive military strategy toward Iran following Trump's assassination of Iranian Gen. Qassem Soleimani. While other Fox personalities lauded the strike, Carlson condemned it, arguing Trump had been "out-maneuvered" by advisers who want "war despite what the president wants." A few days after Carlson's show, which also warned that war with Iran would hurt the president's political fortunes, Trump de-escalated.

"We have come to the point at which pretty much the only thing standing between America and a new war is a prime-time conservative talk show host," commented The American Conservative's Rod Dreher after Carlson's first anti-war intervention. Now, perhaps, we have come to the point at which pretty much the only thing that may convince Trump to stop dismissing the gravity of mass coronavirus infection as a partisan "hoax" is that same Fox pundit.

Yikes. Carlson's influence may work out for the best on these two issues, but surely it's obvious how imprudent it is to rely on his effectiveness and goodwill to determine major governance decisions.

For one thing, Carlson is notoriously changeable: He was a big free-market guy until quite recently; now he praises Sen. Elizabeth Warren (D-Mass.) for her "economic nationalism." Carlson has also proven himself dishonest, unethically partisan, and basically untroubled by his own history of indisputably racist and sexist remarks. In this very Monday monologue, he pointedly labeled the epidemic "Chinese coronavirus," a technically correct nativist dog whistle. In short, Carlson is not a reliably good influence on the president, whatever your idea of good political influence may be.

More troubling than anything about Carlson's personally, of course, is having an immensely powerful president who sometimes decides to be chiefly influenced by a cable news talking head. This is closer to a mad king and his favored courtier than anything like representative government. I have few illusions about Congress' competence or interest in checking executive authority (or doing much of anything beyond partisan theatrics), but there is at least theoretically a process of congressional accountability with Cabinet-level advisers. There is no accountability — or predictability — in presidential affection for a talk show host.

Carlson's influence over Trump's Iran policy was wise and welcome. If he can persuade the president to stop inaccurately downplaying the risk of COVID-19, good. But whatever its occasional benefits, governance by pundit is erratic at best and a worrisome extension of the presidency's imperial evolution. And it may be unavoidable for a while, as there's no way Trump will turn off his TV.