The height of her husband's battle with COVID-19 brought home the worldwide pandemic to U.S. Sen. Amy Klobuchar in ways that no congressional briefing could ever convey.

Her husband, John Bessler, lay in a hospital bed with a dangerously low blood oxygen level that would not seem to rise.

The two-week ordeal with the respiratory illness in March included a week in the hospital and the gnawing fear that comes with the spreading coronavirus that has put millions of people at risk around the world.

Even before her husband got sick, Klobuchar lived professionally in the eye of a storm that saw desperate public officials try to limit the movements and social interactions of an entire nation.

Meanwhile, she struggled to grasp the speed and randomness with which COVID-19 took control of her own family's life.

"We still have no idea how he got it," Minnesota's senior senator told the Star Tribune in an interview.

No matter how Bessler became exposed to the coronavirus, the results ran counter to what he and his wife had been told. John Bessler was 52 and in good health when the illness struck. He had worked around the clock supporting his wife's campaign for the Democratic presidential nomination without falling ill.

He passed off his initial symptoms as a cold because he belonged to none of the risk groups. He was not elderly. His respiratory system was not compromised. Even if infected, he was one of those people who were supposed to be able to defeat the virus without getting terribly sick.

As Klobuchar fretted over her critically ill husband, she confronted a fundamental truth about the pandemic and the strength of the virus causing it.

"If you have someone that healthy get that sick," she realized, "it can happen to anyone."

When it does happen, Klobuchar discovered, COVID-19 comes with a sense of frustration, fear and helplessness. Bessler's cold symptoms gave way to a fever. For 10 days, his temperature stayed above 100 degrees. He coughed up blood.

He asked for a COVID-19 test and got one. It took 5 ½ days to get the results. Klobuchar had been pushing for more testing and more immediate results employing technology like some being developed at Mayo Clinic in Minnesota. Now, she grasped firsthand why that was so important.

Before his test results arrived, Bessler went to the emergency room bothered by his persistent, sometimes bloody cough. Klobuchar expected her husband to get some tests and return home to their Washington apartment. Instead, doctors admitted him to the hospital. An X-ray showed pneumonia, and his blood oxygen level was 68, dangerously below normal.

Shortly after being hospitalized, Bessler got his test results. They confirmed COVID-19.

Klobuchar badly wanted to see her husband. But like others with infected family members, she knew she should stay away to keep from getting infected. In any case, hospitals across the country had started closing to visitors.

"That's one of the hardest things for everyone," she said. "They can't be with their loved ones."

Klobuchar worried about Bessler's survival. "There was a point where he just wasn't getting better," she said. "I never said it to him because I couldn't go see him. But you start to wonder. You just go on with your day because you can't be there. So you say, 'OK, I'm going to go vote on this. I'm going to do this and that.'

"Then they say, 'You know, it's getting worse. The oxygen is getting worse.' And you can't go there to see it yourself. You can't even go to thank the health care providers who are there. Everything is over the phone. So it feels so distant. And it makes it, in a way, scarier."

Abigail Bessler, Klobuchar and Bessler's daughter, was worried, too, her mother said. She wanted to come from New York City to see her dad. But that was not possible because New York was under a restricted movement order issued by the governor.

After five days in the hospital, John Bessler took a turn for the better. "He had oxygen and antibiotics [to treat pneumonia]," Klobuchar said. "He never got to the point of needing a ventilator."

Doctors discharged Bessler on March 26. He remains sequestered in the family apartment. Klobuchar lives temporarily with Minnesota's other senator, Tina Smith.

Klobuchar thinks her husband's case shows why it is not yet time to reopen businesses or reduce restrictions on large gatherings. COVID-19 cases "are on the rise," she said. "And they are on the rise big time. More and more people are dying."

Her family's crucible shows why mass testing with quick results and edicts to avoid contact with those who are ill or might become ill really matter, Klobuchar added. Bessler's choice to isolate himself when he did not believe he had COVID-19 was still advisable in what health officials say is a bad flu season.

"He did not infect people, because even with a cold he decided not to take the risk and he stayed in the apartment," Klobuchar said. "He followed the rules. As a result, I know less people got sick."