WASHINGTON — The Supreme Court’s decision to reinstate much of the Trump administration’s travel ban while it considers the merits of the case is potentially good news for many who want entry into the United States, but may be a bad blow for refugees, experts said.

However, uncertainty surrounded the impact of the high court's action. Several federal agencies must now decide how they will implement it, and advocates warned the confusion itself is harmful, given the delicacy of the refugee process.

“We know that people are going to be hurt by this, and there will be a lot of disruption and dislocation,” said Lavinia Limón, president and chief executive of the U.S. Committee for Refugees and Immigrants, one of nine nonprofits that helps resettle refugees.

“There are people told they were going to fly next week after waiting two years, who maybe sold their possessions and are all packed,” Limón added. “It’s just cruel to imagine that after fleeing war and waiting years finally you’re ready to go next week and guess what? This is what happens.”

The Supreme Court justices overturned a series of lower court rulings to green-light enforcement of much of Trump’s executive order. The court's action temporarily imposes tough restrictions on travel from six Muslim countries — Iran, Sudan, Syria, Libya, Somalia and Yemen — and the entry of all refugees until the court hears the case this fall.

On Tuesday, former acting attorney general Sally Yates said at the Aspen Ideas Forum that the Department of Justice first found out about Trump's travel ban by reading about it in The New York Times. She described how her deputy called her and said he had just been on the Times website and “it looks like the president has instituted some sort of travel ban."

President Donald Trump hailed the court decision Monday as a “clear victory for our national security” that “allows me to use an important tool for protecting our nation's homeland.”

Mark Hetfield, the president of HIAS, a longtime immigrant aid organization, called the court's action "mixed news for human rights, for refugees, and for those non-citizens whom President Trump is trying to ban from the United States based solely on their place of birth.

"HIAS welcomes the ruling as an affirmation that the president does not have unfettered, unchecked authority to bar refugees from the U.S. without evidence to justify such action, and that people with ties to the U.S. can continue to enter," he added. "We are very disappointed, however, that others will continue to be arbitrarily excluded and that the executive order has been resurrected to once again cause irreparable damage to refugees, immigrants, and America’s reputation as a welcoming country.”

Who will be affected?

While the court ruled the ban could partly take effect while it makes a final decision later this year, it said the ban could not apply at this time to anyone with “a credible claim of a bona fide relationship with a person or entity in the United States.” That includes anyone with a family member, an employer, or a school they’re attending in the U.S., the court said in its unsigned ruling, which did not draw dissents from its centrist and liberal justices.

Even before Trump’s executive order, however, few people without some kind of relationship in the U.S. were able to get visas from the six affected countries.

“Our impression is the vast majority of people would still be able to travel because they have a pre-existing relationship, either through family or work,” said Betsy Fisher, the policy director at the International Refugee Assistance Project, one of the plaintiffs in the case. “That is the nature of visa requirements.”

For instance, of the 12,998 immigrants who entered the U.S. from Yemen last year, nearly all — 12,563 — had family in the country, according to State Department data.

The ruling envisions a process where migrants with a link to the U.S. may present their “credible claim” and be exempted from the travel ban. Immigration experts note, however, that may be more complex than it sounds.

First, some migrants in the current process tend to minimize links to the U.S. when applying for temporary visitation because those links can be held against them as evidence they would have reason to overstay a temporary visa (in order to be with their family, for example).

Second, some experts warn a new, court-mandated test will lead to more discretion for border officials — and potentially more confusion.

“It is hard to know numerically how many” people will be impacted, said immigration attorney Greg Chen, depending on how the court’s "bona fide" relationship test is interpreted and applied.

David Leopold, a former president of the American Immigration Lawyers Association, said a rough estimate would be that about half of people lawfully admitted from the six countries would be exempt under the new ruling, citing U.S. “connections, permanent residents and people with visas who went home.”

He noted the court’s test leaves open questions that federal agencies in the Trump administration will have to answer.

“If an American company is hiring someone — researchers or doctors from Iran — are they going to say no ‘bona fide relationship’ at the time order went down?” Leopold asked.

Greg Siskind, an immigration attorney and blogger, noted that the court said student and work visas are by definition exempt, since they require a relationship in the U.S.

That leaves people traveling on tourist visas who could be banned.

“There’s never been a large number of tourists that come from those countries,” Siskind noted, since travelers have to prove somehow they plan to return to their countries and not stay in the U.S.

What about refugees?

The picture is potentially very different for refugees, though it’s unclear at the moment.

Resettlement agencies and advocates are waiting anxiously to see how the Departments of State, Justice and Homeland Security will interpret the high court’s decision.

The State Department said Monday it would implement the ruling in an "orderly manner" and have more to say on the matter after consultation with the Departments of Justice and Homeland Security.

Specifically, the big question for the agencies is whether a refugee's relationship with a U.S.-based refugee organization satisfies the standard set by the Supreme Court, experts said.

“Does having 'a bona fide relationship' mean a resettlement agency you’ve already been working with? You could legally argue that,” said Hans Hogrefe, director of policy and advocacy for Refugees International. “The examples given [in the court's decision] do not cite that.”

“The court standard has a lot of discretion built into it,” said Leah Litman, a professor at the University of California at Irvine Law School and a contributor to the Take Care law blog. “So there’s just little indication on the numbers of the people who are going to be subject to this.”

Alex Seitz-Wald reported from Washington, and Daniella Silva from New York.

CORRECTION (June 27, 2017: 10:18 a.m.): An earlier version of this story included a quotation from Greg Siskind, an immigration attorney, saying that green-card holders could potentially be affected by the Supreme Court’s ruling. In fact, as Siskind noted after publication of the story, the ruling will not affect green-card holders. Siskind's quotation has been removed.