( AP )- Millions of air travelers may find going through airport security much more complicated this spring, as the Bush administration heads toward a showdown with state governments over post-Sept. 11 rules for new driver's licenses.
By May, the dispute could leave millions of people unable to use their licenses to board planes, but privacy advocates called that a hollow threat by federal officials.
Homeland Security Secretary Michael Chertoff , who was unveiling final details of the REAL ID Act's rules on Friday, said that if states want their licenses to remain valid for air travel after May 2008, those states must seek a waiver indicating they want more time to comply with the legislation.
Chertoff said that for any state which doesn't seek such a waiver by May, residents of that state will have to use a passport or certain types of federal border-crossing cards if they want to avoid a vigorous secondary screening at airport security.
"The last thing I want to do is punish citizens of a state who would love to have a REAL ID license but can't get one," Chertoff said. "But in the end, the rule is the rule as passed by Congress."
The plan's chief critic, the American Civil Liberties Union, called Chertoff's deadline a bluff - and urged state governments to call him on it.
"Are they really prepared to shut those airports down? Which is what effectively would happen if the residents of those states are going to have to go through secondary scrutiny," said Barry Steinhardt, director of the ACLU's technology and liberty program. "This is a scare tactic."
So far, 17 states have passed legislation or resolutions objecting to the REAL ID Act's provisions, many due to concerns it will cost them too much to comply. The 17, according to the ACLU, are Arkansas, Colorado, Georgia, Hawaii, Idaho, Illinois, Maine, Missouri, Montana, Nebraska, Nevada, New Hampshire, North Dakota, Oklahoma, South Carolina, Tennessee and Washington.
Maine officials said Friday they were unsure if their own state law even allows them to ask for a waiver.
"It certainly seems to be an effort by the federal government to create compliance with REAL ID whether states have an interest in doing so or not," said Don Cookson , spokesman for the Maine secretary of state's office.
The Sept. 11 attacks were the main motivation for the changes: The hijacker-pilot who flew into the Pentagon, Hani Hanjour , had four driver's licenses and ID cards from three states.
The Homeland Security Department and other officials say the only way to ensure an ID is safe is to check it against secure government data; critics such as the ACLU say that creates a system that is more likely to be infiltrated and have its personal data pilfered.
Congress passed the REAL ID law in 2005, but the effort has been delayed by opposition from states worried about the cost and civil libertarians upset about what they believe are invasions of privacy.
Under the rules announced Friday, Americans born after Dec. 1, 1964, will have to get more secure driver's licenses in the next six years, over which time the new requirements would gradually be phased in.
A key deadline would come in 2011, when federal authorities hope all states will be in compliance, and the regulations would not take full effect for all Americans until 2017.
To make the plan more appealing to cost-conscious states, federal authorities drastically reduced the expected cost from $14.6 billion to $3.9 billion, a 73 percent decline, said Homeland Security officials familiar with the plan.
By 2014, anyone seeking to board an airplane or enter a federal building would have to present a REAL ID-compliant card, with the notable exception of those older than 50, Homeland Security officials said.
The over-50 exemption was created to give states more time to get everyone new licenses, and officials say the risk of someone in that age group being a terrorist, illegal immigrant or con artist is much less. By 2017, even those over 50 must have a REAL ID-compliant card to board a plane.
Among other details of the REAL ID plan:
_The traditional driver's license photograph would be taken at the beginning of the application instead of the end so that if someone is rejected for failure to prove identity and citizenship, the applicant's photo would be kept on file and checked if that person tried to con the system again.
_The cards will have three layers of security measures but will not contain microchips as some had expected. States will be able to choose from a menu which security measures they will put in their cards.
_After Social Security and immigration status checks become nationwide practice, officials plan to move on to more expansive security checks. State DMV offices would be required to verify birth certificates; check with other states to ensure an applicant doesn't have more than one license; and check with the State Department to verify applicants who use passports to get a driver's license.