WASHINGTON -- Monday's U.S. Supreme Court decision that allows Arizona police to check peoples' immigration status means that H-1B workers in the state should have their visa documents available at all times, immigration attorneys say.

The court struck down several parts of Arizona's immigration law but nonetheless left in place a core provision -- the so-called "show me your papers" clause -- that allows police officers to check the immigration status of people in the state at specific times.

If police stop or arrest someone that they also suspect may be an illegal immigrant, they can under the law check that person's immigration status, the court ruled.

The Supreme Court ruled that police can't simply stop an individual and ask for his immigration papers simply because of his race, color or national origin.

However, a traffic stop, for instance, could be the trigger for an inquiry.

How complicated this gets may depend on the training of the police officer on the scene, his knowledge of work visas, and whether an H-1B worker in the state has an Arizona driver's license.

An Arizona state driver's license provides the presumption of legal residency.

Nonetheless, H-1B workers carrying the proper documents might face difficulties because of the immigration law, potentially experiencing delays or even detention, especially if they're dealing with officers and departments that are unfamiliar with immigration documentation, say attorneys.

It's believed that most H-1B workers do not routinely carry visa paperwork at all times because they're concerned that it could be lost. It can take months to replace lost documents, immigration attorneys noted.

Michael Wildes, managing partner at Wildes & Weinberg, an immigration law firm in New York, says his firm is advising clients -- "especially those in the Arizona corridor of the nation" -- to carry proper documentation of their legal status.

Wildes & Weinberg has always recommended that people from other countries make a habit of carrying the proper paperwork, but he said "it's particularly crucial" to do so in light of the recent Supreme Court ruling.

Foreign workers should always carry their visas and passports, their I-797 approval forms, and their I-94 arrival-departure records, said Wildes.

The practical advice for work visa holders as a result of this decision is to carry documentation, said Marko Maglich, an immigration attorney at White & Case in New York. H-1B workers who haven't been in the habit of carrying their documents "better do it now," he said.

It's uncertain how this law will play out in the state over the long term.

If an H-1B worker who carries, say, a California driver's license is pulled over in Arizona, there's no presumption of legal status -- that is only conferred by an Arizona driver's license, said Jorge Lopez, an attorney in the Miami office of Littler Mendelson who co-chairs the law firm's immigration and global migration practice group.

Lopez said visa holders should at least carry copies of their pertinent documents.

Eleanor Pelta, the president of the American Immigration Lawyers Association, said temporary visa holders are not required to carry their documents in Arizona, but they "may feel more comfortable carrying paperwork showing their legal status" because of the ruling.

The Supreme Court's decision "leaves a door open to challenge the 'show me your papers' provision as applied in a particular instance," said Pelta, an immigration attorney in the Washington office of Morgan, Lewis & Bockius. "It is possible that [the law] may still be challenged and struck down in another suit."

Patrick Thibodeau covers SaaS and enterprise applications, outsourcing, government IT policies, data centers and IT workforce issues for Computerworld. Follow Patrick on Twitter at @DCgov, or subscribe to Patrick's RSS feed . His email address is pthibodeau@computerworld.com.