Donald Trump again pressed the powers of the Office of the President to a potential legal breaking point, declaring his “authority is total” – a contention experts say is false as the president appears poised to set up a legal showdown over opening the country amid the coronavirus outbreak.

Minutes later, his vice president, Mike Pence, would only say under questioning about whether he agreed, that in times of war and crisis the powers of the presidency are “unquestionably plenary”.

But Mr Trump appeared to suggest the office has unlimited power at all times. Legal scholars on both side of the aisle dispute his contention, although the president does possess broad war powers.

Mr Trump announced in a Monday morning tweet he is the lone official in the country who can issue an order opening up the country amid the pandemic lockdown.

“For the purpose of creating conflict and confusion, some in the Fake News Media are saying that it is the Governors decision to open up the states, not that of the President of the United States & the Federal Government. Let it be fully understood that this is incorrect....” Mr Trump wrote on Twitter. “...It is the decision of the President, and for many good reasons.”

Some governors have signalled they likely will ignore such an order, contending they have the power to open up their economies and life inside their borders. Groups of east and west coast states say they intend to ban together to open up at the same time once conditions allow.

But Mr Trump again on Monday contended “Americans want to get back to work,” and suggesting the economic hit of keeping the current conditions in place for much longer could be too dire.

Asked to pinpoint which part of the Constitution gives him the power to overrule state chief executives, his answer was a political argument, not a legal one: “Well, if some states refuse to open, I’d like to see that person run for election.”

Some experts say such a spot in that document does not exist.

“Can president Trump order them to change course? The short answer is no, unless he wants to disregard the Constitution,” according to William Galston, a former Clinton White House aide, now with the Brookings Institution.

Mr Trump’s claims about the powers of his office became the main theme of the briefing as there were over 572,000 confirmed cases in the United States and over 23,000 deaths, according to Johns Hopkins University.

Before Mr Trump addressed reporters, US stock indexes had another day of losses after last week’s comeback, which the president touted as the biggest since the last-1970s and a sign of resilience within the economy put there largely by his policies.

The Dow Jones Industrial Average fell 329 points and the S&P 500 lost 1 per cent of its total value on Monday.

The president again spent much of his morning on Twitter, including tweets declaring that he – and he alone – has the legal authority to issue an order that would be pending in all 50 states to reopen the economy and daily American life.

“For the purpose of creating conflict and confusion, some in the Fake News Media are saying that it is the Governors decision to open up the states, not that of the President of the United States & the Federal Government. Let it be fully understood that this is incorrect....” Mr Trump wrote on Twitter. “...It is the decision of the President, and for many good reasons.”

But experts disagree.

“I say there’s close to a 0% chance that the White House doesn’t have a shiny new Office of Legal Counsel opinion arguing a president’s authority is “plenary” in times of crisis. If so, the opinion is worth considerably less than the used surgical glove I saw lying in grass today,” tweeted Walter Shaub, who was White House ethics chief under Barack Obama. “This is insanity and extremely dangerous.”

Another analyst said there is no “inherent authority” in the Constitution to support Mr Trump’s claims.

“No federal statute gives the president the authority to override state decisions. Nor does he possess this inherent authority under Article II of the Constitution. Nor do any other provisions of the Constitution,” according to William Galston, who was a Clinton White House official. “If governors choose to disregard his call to reopen their states, their decisions will be final, and President Trump will have to live with them.”