NEW YORK — As soon as next year, a driver's license may no longer be enough for airline passengers to clear security in some states, if the Department of Homeland Security has its way.
Federal officials said they would soon determine whether Transportation Security Administration agents would start enforcing a 10-year-old law that requires states to comply with a set of federal standards when issuing driver's licenses.
The issue is quickly coming to a head, and the debate over identification and privacy has only intensified after the recent terrorist attacks in Paris and California.
But some states have bitterly opposed these requirements out of privacy concerns, and more than a dozen have passed laws barring their motor vehicle departments from complying with the law, according to the National Conference of State Legislatures.
Massachusetts is among the states that have received an extension for complying with the law.
The new standards require more stringent proof of identity and will eventually allow users' information to be shared more easily in a national database.
Privacy experts, civil liberty organizations, and libertarian groups fear the law would create something like a national identification card.
Federal and state officials have been arguing for years about the merits of the law, called the Real ID Act, which was enacted by Congress in 2005 following the recommendations of the 9/11 Commission. Its proponents argue that it is a necessary tool to reduce identity theft and fraud and enhance the nation's security.
The federal government cannot force states to adopt these identification standards, but it can gain compliance in other ways.
In October, it began requiring that visitors to military bases, nuclear plants, and federal facilities produce a driver's license from a state that complies with the law, or show another form of government identification, like a passport.
But the biggest leverage the government has over the states is commercial air travel.
The Department of Homeland Security said it would provide a schedule by the end of this year for when airport screeners would start accepting only driver's licenses that complied with federal standards.
It said that any announcement would come with a notice of 120 days before starting to enforce the law at airports.
Passengers who do not have a compliant type of identification will have to produce another type of government-approved identification.
"This is a game of intimidation being played out between Congress and the federal government and state governments, with ordinary citizens being squeezed in the middle," said Edward Hasbrouck of the Identity Project, a privacy advocate.
The Department of Homeland Security deems most states to have made enough progress that it has certified or provided extensions to all but a few, including Minnesota, New Mexico, and Washington.
Even so, the deadline could be extended again. Hasbrouck said he did not believe that the government would risk turning back travelers who could not provide the right identification card at airports.
"There is an impasse," Hasbrouck said. "There has been a standoff for more than a decade now. The feds have limited powers to coerce the states in this case."
Homeland Security officials insist there will be no more delays. In recent months, federal officials have visited Minnesota and other states to stress that the clock was ticking. The message was that while participation was voluntary, there would be consequences for failing to comply.
"The federal government has quietly gone around and clubbed states into submission," said Warren Limmer, a state senator in Minnesota and one of the authors of a 2009 state law that prohibits local officials from complying with the federal law. "That's a pretty heavy club."
The law sets some minimum requirements for states to follow when issuing driver's licenses. For instance, it requires applicants to provide documents to prove their identity, Social Security number, and immigration status in the United States.
The new standards also require that licenses be equipped with "machine readable" technology, like a chip or a magnetic strip, to store all that personal information. Data from one state should also be made available electronically to all other states, and possibly also to federal authorities.
That information will eventually be shared through a system administered by the American Association of Motor Vehicle Administrators, a private group that provides support services to state motor vehicle departments.
A press officer for the Department of Homeland Security said the intention of the law was not to create a national identification card but to extend what the agency calls best practices on issuing driver's licenses that apply to all states.
Still, sharing large amounts of private information across states makes some privacy advocates nervous.
Marc Rotenberg, the president of the Electronic Privacy Information Center, said he agreed with some provisions of the law, which are meant to make driver's licenses more tamper-proof and less vulnerable to counterfeiters. But he is concerned with all the information being available on the cards in a way that makes it easier to share.
Some states have objected to the law on the grounds that it imposes too high a cost. The government estimates that the program will cost $3.9 billion, and it has provided grants to states that are moving ahead.
But some critics said that figure vastly underestimated the costs, and they often cite an early study from 2006 that puts the cost at $11 billion over five years.
While many states — including Maine, Missouri, and Montana — do not participate in Real ID, they have issued licenses that share many of the standards that the federal government has required.
This explains why most states are deemed to be in compliance or have received extensions to comply with the law. Still, some critics of the law say it may only be a matter of time before all states fall into line.