If you doubted that President Trump’s approach to the coronavirus crisis is all about him — about getting a few hours or a few days of blaring headlines and then manically moving on to some other empty gesture that he can claim is “strong” — his threat on Saturday to quarantine the New York region tells you all you need to know.

The man who fleeced innocent souls through what the conservative National Review called the “massive scam” of Trump University is applying the same hucksterism to a situation where thousands of lives are at stake.

The quarantine caper ought to be the straw that breaks the hustler’s back.

There was Trump telling reporters in the early afternoon: “There is a possibility that sometime today we’ll do a quarantine, short term, two weeks, on New York, probably New Jersey, certain parts of Connecticut,” he said, expressing worry that “a lot of New Yorkers are going down” to Florida.

Media-wise, all hell broke loose.

Of course he had never spoken to the governors of the affected states beforehand. Of course this was a way of shifting blame for his own incompetence to the stricken people of three Democratic states that would never vote for him. Of course he never considered whether he even had the power to do what he claimed he might do.

And of course it was all fake.

Having milked the “possibility” for a long news cycle, he informed the world on Twitter at 8:19 p.m. Saturday: “A quarantine will not be necessary.”

There are two lessons here. The first is that the media must treat Trump the way they treat anyone else who regularly offers lies along with idle but explosive conjecture. His daily journey before the White House cameras is no different from any of his other swindles, and his “briefings” should be treated with the contempt they deserve.

He uses them to threaten anyone who criticizes him, stages praise sessions from the sycophants who work for him, and makes sham announcements with all the solidity of tissue paper. (“I’d love to have it open by Easter,” he said of the economy. That would have been April 12; on Sunday night, he announced an extension of the social-distancing guidelines to April 30.) He has squandered the right to any of the deference usually accorded presidents in times of crisis.

The second lesson is more important for the long run. We are learning, in both good ways and bad, about the importance of competent, energetic and empathetic government. For the past week, Senate Minority Leader Charles E. Schumer (D-N.Y.) has been offering a running seminar on this subject for all who will listen, both in a floor speech and in a phone interview from his home in Brooklyn.

In voting — unanimously in the Senate — for a $2.2 trillion economic rescue bill, Schumer told me, Republicans acknowledged what they regularly deny: that government is indispensable, especially “when there’s an emergency, when lives are at stake, and when you need quick action.” Also: when “the private sector cannot do the job.”

“It’s a little bit of an awakening for them,” Schumer observed of his GOP colleagues, “that yes, you need a government here.”

But the other side is that government needs to know what it’s doing. Here, the Trump administration has reminded us of how things can fall apart when it doesn’t — when “good, substantive people leave” public service.

“The agencies are hollowed out,” Schumer said. “Where you normally go to call somebody . . . there’s no one home in the White House. This happened over and over again, but it’s more urgent now.”

So, yes, worry about how quick and effective the Trump administration will be in getting the money Congress just provided to Americans in need and to failing small businesses. And it will be important to fight Trump’s already declared resistance to transparency when it comes to the billions that will be handed out to big corporations.

“We’re going to have to oversee the executive branch like a hawk to make sure they do things,” Schumer said. But he warned: “We can give him the resources and we can put a lot of public pressure on him, but ultimately if he’s resistant to the right arguments and the public pressure, there’s no way to actually force him.”

No, there isn’t, but the pressure must be brought nonetheless — by Congress, by governors of both parties struggling for resources, and by the media. Success depends on denying Trump the ability to displace our focus from the things that matter to his carnival of fanciful proclamations, reprisals against enemies, and sweeping promises that are as disconnected from reality as he is from the truth.