He fingered the microphone and put his lips up close. He shook hands with everyone he could. Donald Trump, who promised you’re going to win so much you’ll get sick of winning, might also just make you sick.

In the White House rose garden on Friday, the US president defied the advice of medical experts standing behind him and behaved like a one-man coronavirus cannon.

Trump declared a national emergency (“two very big words”, said the man known for his misspelled tweets) that would release up to $50bn to combat the pandemic, which this week topped 2,000 cases and had the lamps going out all over America.

Reporters wanted to know whether this 73-year-old man with a poor diet – his former doctor reportedly hid cauliflower in his mashed potatoes – is putting himself and others at risk. Brazilian president Jair Bolsonaro’s press secretary tested positive for coronavirus days after taking part in meetings with Trump at his Mar-a-Lago estate in Florida.

Donald Trump declares national emergency over coronavirus pandemic Read more

Should Trump therefore self-isolate? “Well, I don’t know that I had exposure, but I don’t have any of the symptoms,” he replied. “And we do have a White House doctor and, I should say, many White House doctors, frankly. And I asked them that same question, and they said, ‘You don’t have any symptoms whatsoever.’ And we don’t want people without symptoms to go and do the test. The test is not insignificant.”

But later another reporter pushed him harder, noting that a person without symptoms might still be infected. Question: “Are you being selfish by not getting tested and potentially exposing – ”

Trump: “Well, I didn’t say I wasn’t going to be tested.”

Question: “Are you going to be?”

Trump: “Most likely, yeah. Most likely.”

Question: “When do you think that will happen?”

Trump: “Not for that reason, but because I think I will do it anyway. Fairly soon.”

Coronavirus is a crisis of a different magnitude from those faced by Trump before. It has upended daily life and left liberals cursing the cosmic dice: how come Tom Hanks is infected while Trump gets off scot-free?

When the celebrity businessman has his back to the wall, he calls for the cavalry of corporate America. At Friday’s press conference he rolled in business titans to save the day, treating them to plenty of handshakes and little social distancing.

“You’re going to be hearing from some of the largest companies and greatest retailers and medical companies in the world,” he said, presumably hoping to reassure the stock market. “They’re standing right behind me and to the side of me ... they’re celebrities in their own right.”

Trump announced that “drive-thru” testing centers would be set up in parking lots at CVS, Target, Walmart and Walgreens stores.

This, he hopes, will resolve a spectacularly awful time lag in testing kits being made available. America has been put to shame by South Korea.

Trump seems eager to wash his hands of the matter, if not actually wash his hands

The wartime president Harry Truman used to keep a sign on his desk that said: “The buck stops here.” Trump, however, seems eager to wash his hands of the matter, if not actually wash his hands. “Yeah, no, I don’t take responsibility at all, because we were given a set of circumstances and we were given rules, regulations, and specifications from a different time,” he said. “It wasn’t meant for this kind of an event with the kind of numbers that we’re talking about.”

Then Yamiche Alcindor of PBS asked why, in 2018, Trump had dissolved the White House’s National Security Council directorate for global health security and biodefense.

Like a schoolboy caught red-handed, he blustered: “Well, I just think it’s a nasty question because what we’ve done is – and Tony has said numerous times that we’ve saved thousands of lives because of the quick closing. And when you say ‘me’, I didn’t do it. We have a group of people I could – ”

Alcindor followed up. Trump rambled: “It’s the – it’s the administration. Perhaps they do that. You know, people let people go. You used to be with a different newspaper than you are now. You know, things like that happen.”

It is not the first time he has resorted to the word “nasty” when asked a tough question by a woman of colour.

The buck stops here.