■ Soldiers around the world are enforcing lockdowns.

Around the world, as a consensus has formed around the need for quarantine and social distancing to fight the coronavirus, a more delicate question has emerged: How do you enforce those new rules?

In every region, under all kinds of political systems, governments are turning to increasingly stringent measures — and deploying their armed forces to back them up.

Countries as varied as China, Jordan, El Salvador and Italy have sent soldiers into the streets. Guatemala has detained more than 1,000 people. In Peru, those who flout government restrictions can be jailed for up to three years. In Saudia Arabia, it’s five.

At no time since World War II have so many nations wrestled with what it means to be in a state of emergency, and how to impose fundamental and sudden changes in human behavior.

Deploying troops is a startling but often effective way to keep people indoors, but its impact could ripple well beyond the end of coronavirus, as countries decide when — and if — to cede the powers endowed by a global pandemic.

In Lebanon, Chile and Hong Kong, beset for months by protests, fear of the coronavirus has allowed the state to ban public gatherings without overtly violating civil liberties. In several countries, leaders have used the public health crisis to suppress freedom of speech and other constitutional protections.

“It’s really easy to ratchet up these kinds of powers and really hard to ratchet them back down,” said Juliette Kayyem, an assistant secretary of homeland security in the Obama administration. “Once the military is seen as a solution to a public health problem, it’s hard to get the military out of the way.”