Mr. DeSantis and Dr. Atlas appeared together at events across Florida in late August, promoting in-person instruction at schools and colleges, including the return of fall sports.
A spokeswoman for Mr. DeSantis credited him as an innovator who understood that lockdowns were “ineffective,” had come up with a data-driven approach and had remained “singularly focused” on protecting older residents and others most at risk of dying.
In September, Mr. DeSantis’s office placed a call to Dr. Jay Bhattacharya, a professor at Stanford who had criticized coronavirus lockdowns as harmful. In an interview, Dr. Bhattacharya said the call had come more or less out of the blue, and he was pleasantly surprised to learn that the governor seemed to have studied his work.
The governor asked Dr. Bhattacharya to appear on a panel, along with Dr. Martin Kulldorff from Harvard, who with Dr. Bhattacharya went on to help draft the so-called Great Barrington Declaration, a treatise that calls for better protecting the vulnerable while others in society “resume life as normal,” an approach that has been fiercely criticized within the scientific community.
The next day, Mr. DeSantis moved forward with a plan to keep Florida open. He allowed restaurants and bars to operate at full capacity, and he prohibited local governments from enforcing mask mandates, curfews and other restrictions.
The country had just exceeded 200,000 deaths, including more than 14,000 in Florida.
It was a devastating toll, but one that would soon worsen.
The science of masks was well-documented, but governors resisted
By fall, Mr. Trump’s own coronavirus diagnosis was dominating headlines, and he was still insisting that the country was “rounding the corner” in the pandemic and that the virus would soon “disappear.”
But inside the White House, health officials knew more was needed to control the crisis.
In a series of unpublicized weekly memos tailored to each state, the White House’s coronavirus task force had been privately pressuring states to do more. The reports recommended that states like Alaska, Georgia and Wyoming embrace face masks. States like Alabama, Louisiana and Mississippi were advised to put more stringent limits on indoor dining.
But those states and others — at least 26 in all — ignored the urgings of the White House, even when new cases were ticking upward.
For Gov. Kristi Noem of South Dakota, the laissez-faire approach was a point of pride. More than perhaps any other state, South Dakota had kept its doors open, hosting Mr. Trump for an event at Mount Rushmore and committing $5 million in federal coronavirus relief funds to enticing tourists.
In the fall, Ms. Noem traveled the country with the help of a former Trump campaign manager, Corey Lewandowski, eager to showcase that her brand of liberty governance was the right one.
In New Hampshire, she told a group of Republicans that one of her strategies was that she “never talked about the number of cases of Covid-19 that we have.”
In Maine, Ms. Noem criticized the state’s restrictions while claiming that her state’s death rate was among the lowest. “Leadership has consequences, and you are all living under some very poor leadership out of your governor’s office,” Ms. Noem told the crowd.
In fact, new cases and deaths have been climbing in South Dakota. A rally that drew hundreds of thousands of motorcyclists to Sturgis, S.D., over the summer is believed to have contributed, in addition to colder weather that pushed many indoors. Ms. Noem also continued to resist a mask order despite urging from the White House.
South Dakota ended the year with one of the highest death rates in the nation — four times Maine’s — though it also mounted one the nation’s most successful vaccination efforts.
Idaho’s governor, Gov. Brad Little, also resisted a mask order, but behind the scenes, he appeared to acknowledge that such action was needed. Bryan Elliot, who heads the health board in a heavily hit region in southwest Idaho, said two of Mr. Little’s advisers had joined a conference call with two board officials to press them to embrace more control measures, including masks.
The request, Mr. Elliot said, included a threat. Any such measure was bound to spark a public backlash, and the intention, it seemed, was that Mr. Elliot’s board would absorb it. If the region did not impose a mask order, the state advisers told Mr. Elliot, the governor’s office would publicly shame him as being responsible for the case numbers.
“It was not appropriate,” Mr. Elliot said.
The decision to further delegate responsibility to local officials opened the door, as it had in many states, to politics and misinformation.
A woman invited to testify at one board meeting, Dr. Vicki Wooll, suggested that it was 5G cellphone networks that were putting people’s health at risk.
One state over, Dr. Ed Zimmerman, the health officer in Washakie County, Wyo., saw his community being inflamed by other conspiracy theories on social media, including suggestions that virus fears had been overblown in an effort to harm Mr. Trump’s re-election campaign.
“It’s a complete relegation of science to the back burner,” said Dr. Zimmerman, who described himself as conservative.
A week after ordering a mask mandate, he was fired.
A dark winter brings record deaths
Against the odds, some states have managed to keep the virus under control.
Washington State, which recorded 37 of the nation’s first 50 coronavirus deaths, has kept in place a steadily adjusting suite of mitigation measures and now ranks 44th in deaths per capita. If the nation had achieved a rate comparable to Washington’s, about 220,000 fewer people would be dead. Vermont has also been among the states with the fewest deaths, thanks in part to a cautious reopening, significant testing and a mask order.
But a year of political division and uncontrolled coronavirus spread has caught up to most of the country.
In recent days, the virus has been accelerating in nearly every state, and deaths were climbing from Arizona to Connecticut. Even New York, which became a national model for virus restrictions and testing after its spring crisis, is seeing a resurgence.
Winter was always the season in which the virus posed the biggest threat, but in many states, residents have also fallen victim to pandemic fatigue, rendering existing controls less effective.