A growing number of Republican governors, including some who had written off mask mandates as unenforceable or unacceptable to freedom-loving Americans, are now requiring people to cover their faces in public — a response to escalating coronavirus outbreaks overwhelming hospitals across the country.

After eight months of preaching personal responsibility in place of mandates, these governors have brought their states in line with much of the world by instituting the simple requirement backed by science but, in the United States, shot through with politics.

Iowa Gov. Kim Reynolds, who once dismissed mask mandates as “feel good” measures, issued a limited order this week, as her state topped 2,000 coronavirus deaths. The state’s senior U.S. senator, 87-year-old Charles E. Grassley, said Tuesday he tested positive for the virus but reported “feeling good.” And a bipartisan group of Midwestern governors, in a joint video address, stressed that widespread distribution of a vaccine was a long way off and advised their constituents that returning to normal sometime next year first required surviving the holidays.

Ohio Gov. Mike DeWine (R) announced a stricter mask mandate across the state on Nov. 11, asking businesses to crack down on customers who don't comply. (Governor Mike DeWine)

“Mask up,” each said in succession.

Among them was Ohio Gov. Mike DeWine, a Republican who backtracked on a sweeping mask mandate earlier this year but recently stepped up enforcement of a statewide order put into place this summer. DeWine on Tuesday also announced a 21-day statewide curfew.

Beyond the Midwest, rules about mask use are tightening in Utah, North Dakota and West Virginia, all of which reported record case counts at least once last week, according to Washington Post data. Other Republican-led states, such as Maryland, are stepping up various restrictions.

The mask mandates arrived as the nation faced a preview of what a deadly winter might bring, with deaths climbing and case counts skyrocketing. At least 159,000 new cases were reported Tuesday, and more than 77,000 people remain hospitalized. And in a sign of deepening anxiety about how President Trump’s refusal to recognize the results of this month’s election might impair the nation’s response to the coronavirus at a critical juncture, the leaders of three major medical associations urged his administration to cooperate with President-elect Joe Biden’s transition team.

Associates of some Republican governors who recently instituted mask mandates said the expectation of a more active federal response under Biden is providing cover for state leaders who have feared blowback from lawmakers in their own party, as well as from Trump’s base. Some on the front lines are now pointing to Trump’s electoral defeat as an opportunity for governors in his party to assert a modicum of independence.

Other Republican governors, meanwhile, reacted to the Democrat’s victory this month by laying down a marker for him, in a sign of how resistance to the president-elect’s more aggressive approach could become a litmus test for GOP die-hards eager to carry Trump’s mantle. South Dakota Gov. Kristi L. Noem’s office said she would not enforce a federal mandate. Mississippi Gov. Tate Reeves pledged to stand in the way of efforts to close businesses in his state.

No Republican governor embodies the party’s tortured response to masks more than North Dakota’s Doug Burgum.

Six months ago, he fought back tears as he begged residents not to stigmatize face coverings. “Dial up your empathy and your understanding,” the Republican implored at a news conference in May. He cried again last month acknowledging that his state was “caught in the middle of a covid storm.”

But empathy and understanding alone have offered inadequate shelter from the storm buffeting North Dakota, which has recently suffered under the fastest-growing case count in the country. Hospitals are so overwhelmed that some are asking infected but asymptomatic workers to keep treating coronavirus patients.

Over the weekend, Burgum traded out tears for the tools of government, implementing a statewide mask mandate. Face coverings are now required inside businesses and at indoor public settings, as well as in outdoor locations where physical distancing is not realistic. Failure to comply could bring a penalty of up to $1,000, though some local authorities are already refusing to enforce the order.

Burgum, a former Microsoft executive whose net worth is estimated at about $1.1 billion, was for months among the GOP governors who did not scorn masks yet shied from statewide mandates. They stressed personal responsibility even as evidence mounted that sweeping rules were associated with a slower growth rate of the virus.

Burgum’s about-face is perhaps the starkest example of the broader shift underway in a handful of Republican-controlled states. Health-care workers say Burgum and other Republicans now have an opportunity to follow science rather than the whims of the White House.

“It was everyone’s assumption that the governor would only act on masks after the election, and here we are,” said Tessa Johnson, president of the North Dakota Nurses Association. A spokesman for Burgum did not respond to a request for comment.

In West Virginia, where Republican Gov. Jim Justice recently tightened the state’s mask requirement, some of the medical experts advising him were frank about the forces working against heightened enforcement of public health precautions.

“He has a deep personal friendship with Donald Trump, but he also believes for West Virginia that mask-wearing is a very vital tool in our tool belt that can save lives and protect people’s health,” said Clay B. Marsh, West Virginia University’s chief health officer and the state’s coronavirus coordinator.

Marsh said mask-wearing is so central to controlling the outbreak that 90 percent compliance would have a greater impact on slowing the spread of the virus than would the arrival of a vaccine. “We believe that we have a vaccine in our hands today, and it’s called masks and physical distancing,” he said.

Paul Carson, an infectious-disease specialist at North Dakota State University who has been advising Burgum on the state’s response, said mandates have not been shown to yield widespread compliance in all places. The intensifying crisis in North Dakota, however, made it necessary to ask for new sacrifices.

“It was becoming apparent to all that our health systems were being stretched to the breaking point, and our nurses were crying out,” Carson said.

The belated reaction stands in contrast to preemptive measures taken in other countries. North Dakota’s mask mandate went into effect Saturday, as the state recorded 2,270 new cases of the virus. Also over the weekend, South Korea began imposing fines for noncompliance with mask requirements as it registered 205 new daily cases — the first time since September the country’s one-day count had exceeded 200.

South Korea, with a population about 70 times that of the Great Plains state, has recorded fewer than 500 coronavirus deaths, while North Dakota has seen nearly 800.

“In some ways, we’ve chosen to make our policies reactive to the waves of the pandemic rather than getting ahead of it,” said George L. Wehby, a health management and policy professor at the University of Iowa and the co-author of a June study finding that mandating masks in public is associated with a decline in the daily coronavirus growth rate.

Brad Anderson, the Iowa director of AARP, said the state’s new rules signal to the public that, “We are facing a crisis like we have never seen before in the state.” But they carry a lesson, too, for leaders who bet for months on the goodwill of residents, he said.

“It’s not enough to expect people to do the right thing without leadership from the top,” Anderson said.

The new rules are especially noteworthy for going into effect shortly after voters denied a second term to Trump, who has treated mask-wearing as a political marker. A Republican in frequent communication with ­DeWine said a more cohesive national strategy could make it easier for the centrist to navigate the political crosscurrents that have at times frustrated his response. Dan Tierney, a spokesman for DeWine, said heightened restrictions were not tethered to the results of the election and instead reflected efforts to overcome the population’s pandemic fatigue.

An aide to Utah Gov. Gary R. Herbert, who spoke on the condition of anonymity to discuss internal deliberations, said the longer the president refuses to accept the results of the election, the longer his shadow will be over the coronavirus response in states where he enjoys widespread support. Herbert, while once favoring local control, resorted recently to a statewide mask mandate because his “appeal to people’s basic sense of decency” was not working, the aide said, adding, “People still don’t believe in the science behind masks.” Protesters appeared at the governor’s home over the weekend to decry the measure.

Governors spared outcry among residents have instead faced revolt within their own ranks. Three North Dakota health officers appointed by Burgum have resigned during the pandemic. The most recent to exit, Paul Mariani, left a day after the governor reversed himself and pulled back an order that would have required close contacts of infected people to quarantine. Mariani declined to comment about the new mask mandate. His replacement, Dirk Wilke, did not respond to a question about the new order.

The mandate will test Trump’s imprint on his party’s response to the virus, said Chet Pollert, the majority leader in North Dakota’s House of Representatives. “Definitely this is a Trump state, and definitely people were following Trump’s lead about masks,” he said.

But the president’s ability to stoke opposition to public health interventions, the lawmaker added, drew on deeper political traditions in the northern Great Plains, he said.

“There’s been this mentality that you have to do this stuff on your own,” Pollert said. “It has served people well when settlement was happening in North Dakota in the late 1800s and through the 1900s.”

Even with a deadly pathogen tearing through the state in this century, Pollert added, he favors a lighter touch. “I’ve just never been a mandate-type person,” he said.

Jacqueline Dupree contributed to this report.