With furious speed and growing alarm, the nation’s governors and mayors have closed down much of American life in recent days.

But the measures to shutter businesses, forbid movement and limit gatherings have gone largely unenforced by the nation’s police departments. Even in places where the new rules have been legally mandated — and violations are punishable by fines or arrest — many commanders have instructed their officers to do everything possible to avoid a criminal case.

Enforcement “is a last resort,” said Sgt. Michael Andraychak, police spokesman in San Francisco, a city that has been under shelter-in-place orders for over a week. “We are not interested in using a criminal justice approach for a public health challenge.”

The leniency reflects the perilous position of law enforcement agencies as they attempt to win the public’s compliance with sweeping restrictions that have no precedent in the nation’s peacetime history. For now, at least, authorities are primarily relying on the public’s voluntary cooperation. Many fear that doing more risks inciting a backlash that would make it even harder to stem the pandemic. And, they note, there’s evidence that the current strategy is working: Urban centers have emptied out; mobility measurements show a dramatic reduction.

Yet scenes of spring breakers out en masse in Florida or families crowding parks from Brooklyn to the Bay Area reflect the limits of a relatively lenient approach — and suggest the United States, with its spirit of rugged individualism, may face particular challenges in trying to suppress covid-19 outbreaks.

In China, the authoritarian government won compliance through coercion. In Italy, authorities have launched drones to ensure people stay indoors. In Britain, police are empowered to fine or arrest those who disobey the nation’s new lockdown orders.

Without more muscle behind the U.S. restrictions, some leaders worry that the country simply won’t be able to get control of an outbreak that is spreading exponentially.

“We are not looking to arrest the world. We are looking for people to comply with the law at a time of crisis,” said Ed Day, county executive in Rockland, just north of New York City. “Not doing so is a matter of life or death.”

In Rockland, as throughout New York, the number of known coronavirus cases has surged in recent days; as of Wednesday afternoon, the county had nearly 1,000 cases out of more than 30,000 statewide.

Day said he has directed the county’s health department to vigorously enforce state directives intended to slow the spread. Last week, inspectors fined a wedding hall $2,000 for breaching a then-statewide order banning gatherings of more than 50 people.

On Sunday, another wedding — this time at a private residence — prompted calls to Day’s office and to police in Ramapo, a town in Rockland. When officers left without breaking up the party, Day took to Facebook to vent his frustration with the police.

“So now there is an expectation that 2 civilian employees from the Health Department are supposed to force the issue with 100 plus people when professional law enforcement officers seemingly are ordered not to do so?” he wrote. “Ridiculous.”

Police later said there had been two events, not one, and that both were under the legal limit. The department wrote on Facebook that it could find “no evidence of any violation of the Executive Order.”

But controversy soon erupted on social media: The wedding had involved ultra-Orthodox Jewish families, and some suggested in response to Day’s post that the police had held back to avoid upsetting a large religious community with political clout in the town. Others jumped in to accuse those commenters of anti-Semitism.

Day, a retired New York City police detective, said officers have understandable concerns about not wanting to infect themselves — or their families — while in the line of duty. But he said stricter enforcement is called for in times of crisis.

“This is an emergency order signed by the governor,” he said. “You do not ignore enforcement of the law. That is just not what cops do.”

But in the current crisis, it’s happening nationwide.

Despite draconian-sounding state edicts, police say they are giving violators the benefit of the doubt and not issuing citations, leveling fines or pressing misdemeanor charges — even when they could.

In some cases, police themselves are struggling to figure out what’s allowed and how they should be handling violations.

“We’re still waiting for a little bit of direction on enforcement,” acknowledged Lt. Paul Cicero, a police spokesman in Hartford, Conn., where new restrictions took effect Monday night. The city, he said, was “not at a point that we’ll be enforcing the statutes.”

In Illinois on Friday, the governor ordered everyone to stay at home, except for essential outings such as visits to the grocery store, and banned people from socializing outside their household. Gatherings of 10 or more people were forbidden.

But Chicago police officers have not been making arrests or doling out fines. Instead, they have focused on education, said Sgt. Rocco Alioto, a spokesman for the force.

If officers encounter a group of 10 or more, “we’re going to let them know about what’s been declared and ask them to disperse, give them a warning,” he said. “If that doesn’t work, we’d give them another warning.”

The reluctance of police commanders to get heavily involved in enforcement makes sense, said Peter Scharf, a criminologist at the LSU New Orleans School of Public Health.

“It’s a very uncomfortable mission for law enforcement,” Scharf said. “They’re used to getting the guy with the sawed-off shotgun. They’re not used to enforcing public health ordinances, especially if there’s a risk to the officer or a risk of bringing illness back home.”

During the 1918 flu pandemic, Scharf said, officers in cities such as Seattle and Boston rebelled against their grim task, which regularly put themselves and their loved ones in danger of falling ill.

There’s also the risk that the public balks as restrictions drag on for weeks or more, the economy tanks and people look for someone to blame for their newfound despair.

In China, members of the public were largely acquiescent as their lives went into lockdown. They had little choice, given the iron grip of state control. The same couldn’t be assumed in the United States, where chafing at governmental authority is a cherished tradition.

The fact that a significant share of the public believes the threat of coronavirus has been exaggerated — a view peddled by some conservative media outlets, and periodically by President Trump — only adds to the challenge.

With much tighter enforcement of restrictions — if it comes to that — there will inevitably be questions about where to draw the line between individual freedom and public safety.

“Are we really comfortable with public health fascism, if you want to call it that? What is the right of the state to command the greatest good for the greatest number? Are there legitimate civil liberty concerns?” Scharf asked.

The task is made even more complex by a legacy of racism built into law enforcement policies, such as stop-and-frisk, that have disproportionately targeted black and Latino communities. Coronavirus-related restrictions that are enforced in some places and not others are bound to be scrutinized for evidence of bias, said Jeffrey Fagan, a professor of both law and epidemiology at Columbia.

“The police have to tread carefully. If they’re seen as overstepping their boundaries and they do it in a way that’s harsh and intrusive, then they’re going to be treated with suspicion and maybe not the greatest cooperation,” he said.

For San Jose Police Chief Eddie Garcia, that concern is now top of mind.

During the first week of stay-at-home orders in the Bay Area, Garcia ordered his department to focus on educating the public and, where necessary, issuing warnings for noncompliance.

“There’s going to be a lot of gray area. Businesses had questions. We had questions. That definition of what is essential and what is nonessential can get difficult,” Garcia said.

But by late last week, Garcia was losing his patience with repeat violators. The city, he said, would begin enforcing the law — issuing misdemeanor citations and threatening business license or health code sanctions for those clearly ignoring the rules.

“I don’t think I need to give a billiards hall another warning,” he said. “We have to send the message that we’re taking this seriously.”

Still, police have been cautious. On Monday, the first day of enforcement, there were no citations issued. And in a city of more than 1 million people, the majority of whom are nonwhite, Garcia has taken care to assure the public that the new orders won’t be used as a pretext to target people for stops.

“We’ve worked hard to built trust,” Garcia said. “We’re going to have a lot of bridges to rebuild if we don’t do this right.”

Steve Burkholder in Middletown, Conn., and Shirley Wang in Iowa City contributed to this report.