3 Baltic States Announced a ‘Travel Bubble.’ What Is It and Could It Work in the U.S.?

Estonia, Latvia and Lithuania plan to open their internal borders for citizens to travel between the three countries beginning on May 15, a decision that creates the first “travel bubble” among European Union countries as coronavirus-related travel restrictions begin to ease.

The announcement, made by the prime ministers of the three Baltic nations on Wednesday, follows a statement made in late April by the prime ministers of Australia and New Zealand, who agreed this week to establish a similar bubble when flights between the countries can be safely arranged. Both Australia and New Zealand, compared to other nations, have made significant progress in containing the coronavirus outbreak within their borders.

People traveling to the Baltic corridor from other countries will continue to be required to go into isolation for 14 days after entry.

“It’s a big step towards life as normal,” wrote Jüri Ratas, the prime minister of Estonia, in a Twitter message.

Regional bubbles — among a group of states, for example — could be a way to get people traveling again and help revive businesses as the world readjusts to life with the coronavirus. Earlier in the pandemic, the governors of California, Washington, Oregon, Nevada and Colorado said that they will coordinate the reopening of their states to limit the spread of Covid-19. A travel bubble among those states might make it easier for residents to travel and work across their borders, though spokesmen for the governors of California, Oregon and Washington said that they have not yet discussed creating such a bubble.

Travel bubbles imposed by nations — where strict immigration rules can dictate who enters and exits — are one thing. But would they be legal within the United States? Maybe not.

“If any states created a bubble to keep out residents of disfavored states, the action would be open to challenge that the bubble violated U.S. Constitutional principles of equal treatment,” said Cam Winton, a lawyer with the firm Dorsey & Whitney, who has been advising people dealing with state-imposed coronavirus rules. “Those principles are enshrined in the Privileges and Immunities Clause, the Equal Protection Clause and the so-called Dormant Commerce Clause, which prohibits states from putting undue burdens on interstate commerce.”

Under its police power, a state can deploy nondiscriminatory public health measures like taking the temperature of everyone entering the state or requiring them to go into quarantine, as long as it imposes that rule on every person, regardless of where the person is from.

Mr. Winton added that neighboring states could enter into agreements for coordination of checkpoints, sharing data and other anti-coronavirus efforts, but those initiatives would all be subject to the constraints on government power conferred by constitutional rights.

In the United States, measures created by some municipalities in recent months have created de facto bubbles, but the porousness of these varies from place to place and would be difficult, if not impossible, to make official without infringing upon the rights of states and citizens, experts said.

In Florida, the Keys have become their own bubble. Since March 22, Monroe County, which includes the islands, has had two checkpoints at the top of the Florida Keys Overseas Highway — one at mile marker 112.5 on the 18-mile stretch of U.S. 1 and the other on County Road 905. Only people who can prove that they live or own property or work in the Keys have been allowed onto the chain of islands that is about 60 miles away from Miami.

When Key West, the seat of Monroe County, began reopening its beaches and parks on Monday for locals, people from neighboring Miami-Dade County tried to drive to the beach but were turned away at the checkpoints.

“Historically we’ve had day trippers come then leave, but Miami-Dade County is a hot spot with a lion’s share of cases, so what we’re trying to do is only allow essential services into the Keys and say that the beach is open only for locals to get out a few hours a day to get sun,” said Teri Johnston, the mayor of Key West. “Our residents want to know that we aren’t relaxing orders in a way that would bring visitors to our island until it is safe for that.”

Officials in Key West have been in conversation with business owners, realtors and the administrators of attractions like museums about a phased reopening of the city, in which everything would reopen to locals first, said Alyson Crean, a public information officer.

“Everyone agrees that opening up to visitors is the last phase,” Ms. Crean said.

For places without the natural geography to help create a bubble, things get murkier. Under Colorado’s new “Safer at Home” policy, people have been ordered by Gov. Jared Polis to limit recreational travel to no more than 10 miles from their homes, and to try to keep essential travel within their county, if possible. Theoretically, those orders would create bubbles that would prevent visitors from traveling to the state’s more isolated areas.

However, Estes Park, a tourist town in Larimer County that is the gateway to Rocky Mountain National Park and 30 miles from the nearest city, recently began allowing its hotels and short-term rentals to reopen with social distancing policies in place.

Kate Rusch, a spokeswoman for the Town of Estes Park, said that essential travelers and people traveling within Larimer County might need accommodations and that the town wanted to be ready for when travel restrictions were loosened further.

But some saw the move as an open invitation to visit. Hattie Serrano, a local resident, wrote in a Tweet that hundreds of people had been visiting even during the shelter-in-place order. “Telling people to stay home and then opening hotels at the same time is contradictory to one another. If the hotels are open they will come. They’ve come despite them being closed. Reopening them is a terrible mistake.”

Others, like Stephen Rapp, objected to staying within the 10-mile bubble. He tweeted that it would be “unconstitutional” to prevent him from staying in his second home in Estes where he normally spends six months of the year and pays taxes. He asked: “I’m an Estes Park property owner, so am I an outsider or not a local?”

In South Carolina, the city of Folly Beach, located on Folly Island, just south of Charleston, found itself in conflict with the state’s governor when it set up checkpoints on the road leading to the island and banned short-term rentals in March. “By creating the checkpoint, we had essentially created a bubble for our island,” said the town’s mayor, Tim Goodwin.

But under an order from the state’s attorney general, officials were forced to lift the restrictions. Mr. Goodwin said people immediately began flooding in. “The day that we did lift the checkpoint we went from an average of 2,000 cars to an average of 10,000 cars,” he said.

On Peaks Island, an island in Casco Bay, Maine, that is 15 minutes away from downtown Portland and is only accessible by ferry, residents recently asked city leaders to encourage people to only take essential ferry trips to the island out of fear that the guests could increase the number of cases already recorded. Some locals worry that people will flood back to the island over Memorial Day weekend.

“It’s a very conflicted situation with community needing the business that comes with visitors, but also needing to prioritize everyone’s health,” said Randy Schaeffer, chair of the Peaks Island Council, which is not a legislative body but an advisory group for the island. “People might want something like a bubble, but we don’t have the legal power to do that and it is highly unlikely that we would be able to keep people from coming here.”

“We aren’t North Korea,” he added.

Karen Schwartz contributed reporting.