“We wouldn’t go nearly as close as China in terms of making those kinds of impositions on civil liberties,” said Glen Mays, professor of health policy at the Colorado School of Public Health.

“As you get further down that list, the calculus the governor or state health official will have to make is, do the risks we face justify the economic and personal-freedom costs of adopting measures like canceling large events, closing schools or banning movement,” Mr. Mays said.

Washington State has led the way in recent days in adopting many public distancing requirements, but cities and states across the country have been imposing restrictions of their own. New York, California, Maryland and other states moved to limit most gatherings of more than 250 people. Ohio, Oregon and others have started announcing extended school closures. Private organizations have also joined the effort, including major sports leagues and Disneyland, which said it would close its theme parks in Anaheim and Orlando, as well as around the world.

California’s governor, Gavin Newsom, said this week that state officials are regularly running table-top exercises that simulate the pandemic becoming more severe.

“We have pandemic plans,” Mr. Newsom said. “They are the kind of plans that keep you up at night.”

On Thursday, he issued an executive order that allows the state to take over hotels should they be needed to treat coronavirus patients. His order also called for canceling or postponing smaller gatherings, if those in attendance cannot remain six feet apart from each other, as well limiting to 10 the number of older and less healthy people at gatherings.

“This is where we need to go next, and to make sure we fully implement those procedures and protocols to slow down the spread to get through a peak and to get through the next few months, so we don’t overwhelm our health care delivery system,” Mr. Newsom said.

He was careful, however, to describe the decision to cancel large events as “guidance,” highlighting that his order had limited legal power and that he did not believe it was necessary to impose forced shutdowns.