WASHINGTON — President Trump’s claim that he wielded “total” authority in the pandemic crisis prompted rebellion not just from governors. Legal scholars across the ideological spectrum on Tuesday rejected his declaration that ultimately he, not state leaders, will decide when to risk lifting social distancing limits in order to reopen businesses.

“When somebody’s the president of the United States, the authority is total,” Mr. Trump asserted at a raucous press briefing on Monday evening. “And that’s the way it’s got to be.”

But neither the Constitution nor any federal law bestows that power upon Mr. Trump, a range of legal scholars and government officials said.

“We don’t have a king in this country,” Gov. Andrew M. Cuomo of New York said on Tuesday, adding, “There are laws and facts — even in this wild political environment.” He rebutted Mr. Trump’s claim by citing a line from Alexander Hamilton, observing that presidential encroachment on powers that the Constitution reserved to the states would be “repugnant to every rule of political calculation.”

Mr. Cuomo is a Democrat, but even some of the most outspoken Republican supporters of a generally sweeping vision of presidential power agreed that Mr. Trump’s claim was empty.

John Yoo, a University of California, Berkeley, law professor known for writing much-disputed Justice Department memos after the Sept. 11 attacks claiming that President George W. Bush, as commander in chief, had the power to override legal limits on torture and surveillance for the war against Al Qaeda, said Mr. Trump could not force states to reopen.

“Only the states can impose quarantines, close institutions and businesses, and limit intrastate travel,” Mr. Yoo wrote in The National Review. “Democratic governors Gavin Newsom in California, Andrew Cuomo in New York, and J.B. Pritzker Illinois imposed their states’ lockdowns, and only they will decide when the draconian policies will end.”

Vice President Mike Pence — who styled himself as a strong proponent of states’ rights when Barack Obama was president — was a lonely voice backing Mr. Trump. “In the long history of this country,” he said on Monday, “the authority of the president of the United States during national emergencies is unquestionably plenary.”

The Constitution bestows specific powers on the federal government while reserving the rest to sovereign state governments. None of the enumerated powers given to the federal government directly address control over public health measures, although the Constitution does let Congress regulate interstate commerce.

Both a pandemic and social distancing measures that require the closure of businesses, to be sure, affect interstate commerce. But even if the federal government in theory could have more power in this area, it would take an act of Congress to bestow it on the presidency.

Lawmakers have created some executive powers relevant to the crisis — including enabling an administration to take steps to keep illness from spreading across state lines and to mobilize industry to ramp up production of needed goods in a public health crisis. But they have passed no statute purporting to give the presidency pre-eminence over governors on rescinding public health limits inside states.

Similarly, while Mr. Trump declared a national emergency over the pandemic, that did not mean he was tapping into some reservoir of limitless constitutional power. Rather, he was activating specific statutes that Congress has enacted creating particular standby powers, none of which include letting a president overturn state-imposed public health safety measures.

In a 1952 case involving President Harry S. Truman’s seizure of steel mills to avert a strike during the Korean War, the Supreme Court rejected his effort to invoke purported “inherent” constitutional power to resolve the crisis using different tools than Congress had provided.

And even if Congress were to now enact a law giving Mr. Trump that power — which is unlikely, with the House in the hands of Democrats — there would still be legal obstacles. The Supreme Court over the last generation has pushed back when Congress has enacted laws that the court sees as federal commandeering of states’ authority.

“The federal government may neither issue directives requiring the states to address particular problems, nor command the states’ officers, or those of their political subdivisions, to administer or enforce a federal regulatory program,” Justice Antonin Scalia wrote in a 1997 Supreme Court ruling.

On Tuesday, Mr. Trump appeared to seek a face-saving way out, saying he was “authorizing” governors to decide for themselves when to reopen their states. He offered no explanation for the implication that his permission was necessary before they could lift their own orders.

For Mr. Trump, the legal emptiness of his assertion fits with a larger pattern in his handling of the pandemic and more. Where President Theodore Roosevelt liked to invoke an African proverb to describe his approach to wielding executive power — “speak softly and carry a big stick” — Mr. Trump sometimes talks as if he has a big stick but with little to back it up.

Despite his “extreme, proud rhetoric about how he can do whatever he wants,” said Jack Goldsmith, a Harvard law professor and senior Justice Department official in the George W. Bush administration, the story of the Trump presidency has been, with few exceptions, “talking a big game, but not in fact exercising executive power successfully.”

Mr. Trump has made greater use of a softer power of the presidency: using his pre-eminent position and the attention he commands for public persuasion, which Roosevelt called the bully pulpit. But Mr. Trump used it at first to play down the crisis, rather than issuing a call to action to galvanize the country to more swiftly take steps like ramping up testing capacity and consider imposing social distancing measures.

Some legal experts theorized that Mr. Trump could try to use the federal government’s control over disaster relief funds and equipment to punish states whose governors reject a hypothetical future White House declaration that it is time to open up.

He could, for example, try to allocate more equipment to states whose governors acquiesce to his desires, which would inevitably lead to litigation. Even so, as Mr. Yoo wrote, such punitive measures are politically unlikely to move Democratic governors in hard-hit areas to reopen their economies before public health experts say it is safe.

Mr. Trump demurred when pressed to say who told him he wielded “total” authority, and his administration has put forward no legal theory.

Some White House officials expressed uncertainty about what the president was relying on. But others pointed to Article II of the Constitution, which creates the presidency and which Mr. Trump has often invoked, and several statutes creating certain public health powers. None of those statutes they cited say a president has total authority to force governors to lift pandemic restrictions.

Indeed, numerous legal scholars rejected Mr. Trump’s claim as baseless, including Jonathan Turley, a George Washington University law professor who testified in the president’s favor during the impeachment inquiry.

“The Constitution was written precisely the deny that particular claim,” Mr. Turley wrote on Twitter.

Complicating the task of parsing the president’s intentions, he often appears to float striking and self-aggrandizing ideas off the cuff, causing consternation before he drops them.

On March 28, for example, he abruptly suggested that he might impose a federal quarantine on the New York City area before reversing course hours later.

It was never clear what he was talking about. While Congress has granted the federal government some power to take steps to prevent the transmission of illness into the country or between states, the virus was already everywhere by then, so sealing state borders would not have kept it contained. And a quarantine that would confine large populations to their homes within a state is widely understood to be a state-level decision.

Yet despite punctuating his performance with claims of his own might, Mr. Trump has repeatedly made less-than-aggressive use of undisputed authorities at his disposal to combat the pandemic.

For example, he has repeatedly boasted about shutting down travel from China in February, using the power that Congress granted to the presidency to control the international border in a public health emergency.

But despite Mr. Trump’s claims that he was the first to take that action, 38 other countries had already put in place such a travel ban. And the American version was limited and porous.

And as it became clear in March that hospitals were hindered by shortages of masks and other equipment, Mr. Trump resisted growing calls to make use of another power Congress gave the presidency for use in a national emergency: to coerce factory owners to change what they are manufacturing under the Defense Production Act.

In late March, Mr. Trump finally declared that he was invoking the law — but he had merely delegated to Alex M. Azar II, the secretary of health and human services, the ability to invoke that law in theory. No company had been ordered to do anything.

As criticism over Mr. Trump’s inaction swelled, he signed an order telling Mr. Azar to use the law to push General Motors to make masks. But G.M. said it had already decided by then to make ventilators in partnership with Ventec, developed plans to source the necessary parts and started preparing a factory in Kokomo, Ind., for production.

Mr. Trump has a history of making head-turning claims about his powers in other contexts. During the Russia investigation, for example, his lawyers argued that he could not be guilty of obstruction of justice because his power over the Justice Department was absolute, and Mr. Trump repeatedly claimed he could fire the special counsel, Robert S. Mueller III, if he wanted — even directly.

“Article II allows me to do whatever I want,” he said.

Yet as the eventual report by Mr. Mueller showed, in practice Mr. Trump’s power was weak. He pushed subordinates to oust the special counsel, but they would not go along.

Mr. Goldsmith said that Mr. Trump’s approach to the pandemic crisis and more had reflected a general pattern of loud words but incompetently executed action on policies that were more complex than basic tasks like issuing pardons and firing people, bogging down his efforts in court battles and dysfunction rather than clear accomplishment.

“Trump wants it to seem like he is this really powerful guy being really aggressive with executive power, but he’s not,” Mr. Goldsmith said. “There has been a huge mismatch between his rhetoric and his actions. He clearly seems to enjoy how people’s heads explode when he says this stuff, even though it’s not matched by reality.”

Maggie Haberman contributed reporting from New York.