Updated

Sept. 11 commissioners told Congress on Monday they want the federal government to set standards for getting driver's licenses (search) to make it harder for terrorists to fake their identities.

Commission Chairman Thomas Kean (search) told the Senate Commerce Committee that ID cards helped terrorists prepare for the Sept. 11 hijackings by allowing them to board commercial flights.

"The time at which terrorists are most vulnerable is when they move around," Kean told the committee.

The Sept. 11 report issued last month said the United States must expand its border security system into a larger network of screening points, including places where people enter the transportation system or other possible targets, such as nuclear reactors.

Amtrak (search) and the airlines already check passengers' IDs before they board.

The commission recommended the federal government issue standards for other forms of identification, such as birth certificates.

"Sources of identification are the last opportunity to ensure that people are who they say they are and to check whether they are terrorists," the report said.

Committee Chairman John McCain, R-Ariz., who said he would file bills to implement the commission's recommendations, indicated he was interested in a national ID card.

"Isn't that a fundamental issue we're going to have to address as a nation?" McCain asked Kean and Commission Vice Chairman Lee Hamilton, who also testified.

The American Civil Liberties Union (search) says a standard driver's license would lead to a national database that would allow the government to keep track of where people go.

"We're objecting to the nationalization of the driver's license and databases that are going to have to be implemented in order to track driver's licenses," said Marvin Johnson, legislative counsel for the ACLU.

Hamilton said federal standards for issuing driver's licenses could lead to a national identification card, but people might accept it.

"The American public is becoming more and more agreeable to intrusiveness in order to protect themselves from a terrorist attack," Hamilton said.

Homeland Security Undersecretary Asa Hutchinson told the panel he didn't read any Sept. 11 commission recommendations that he disagreed with, but didn't explicitly say he supported federal standards for driver's licenses.

Some states have already tightened requirements for getting a driver's license in order to screen out people who try to fake their identities and people who try to hide bad driving records.

Jason King, spokesman for the American Association of Motor Vehicle Administrators (search), said the group wants states to accept a standard set of credentials before issuing a driver's license.

"We must upgrade the practices," said King, whose group represents U.S. and Canadian departments of motor vehicles and highway law enforcement organizations.

King said the ACLU's fears are overblown. "A driver's license is issued independently by a state government, it has its own unique look and it's a voluntary credential. You're welcome to use a military ID or even a passport."

Cheye Calvo, transportation committee director for the National Conference of State Legislators (search), said the states are discussing establishing minimum standards on their own.

"The states have real problems with the federal government coming down with a hard-line single way," Calvo said.