Legislation supporting a standardized national driver's license may have won unanimous approval in the Senate on Tuesday, but the bill's apparently smooth passage left some jagged edges in its wake.

The Real ID Act appeared in take-it-or-leave-it spending legislation, which effectively forced lawmakers to sign on to the whole measure even if they disagreed with a portion of it. Several Republican and Democrat senators who cast favorable votes for the bill simultaneously railed against the provision authorizing the new driver's license rules.

They're not the only ones refusing to accept the bill peacefully. The National Governors Association is threatening lawsuits to fight the legislation. And some states are threatening to ignore the legislation because they say it will cost up to $700 million for states to comply and will place a heavy burden on Department of Motor Vehicles workers.

A spokeswoman for the governors' association did not return calls for comment. But Arkansas Gov. Mike Huckabee, a Republican, told the Associated Press this week that "if more than half of the governors agree we're not going down without a fight on this, Congress will have to consider changing" the rules.

In the meantime, mobilization against the legislation is also occurring on the citizen front. Civil liberties activist Bill Scannell, who launched a website this week to protest the legislation, said that visitors to his site sent more than 20,000 faxes to senators within 24 hours.

"One by one (senators) got up and said, 'This is a real stinker but you've got a gun to our heads so we've got to vote for it,'" Scannell said. "This is an incredibly sleazy way to push something that pushes the very nature and foundations of our democracy."

The act passed in the Senate with a 100-0 vote Tuesday and passed through the House twice – first as a stand-alone bill in February and again last week as part of a larger spending bill. But several senators, such as Lamar Alexander (R-Tennessee) and Dick Durbin (D-Illinois), said the legislation would have unintended consequences and likely wouldn't improve national security.

Marc Rotenberg, executive director of the Electronic Privacy Information Center, said more than 600 organizations – including state legislation associations, civil liberties groups and pro-immigrant advocates – opposed the bill. And he said organizers will gather next week to discuss plans to press Congress to revisit its decision.

"This is one of the biggest mistakes Congress has ever made," Rotenberg said. "This is not over by any means."

Supporters of the bill say it would prevent terrorists and undocumented immigrants from obtaining legitimate documents that would help them move freely through the country. Last year, the 9/11 Commission called for tightening control over government-issued IDs because 18 of the 19 hijackers in the Sept. 11, 2001, terror attacks used U.S. IDs to pass through airport security.

But opponents of the bill say it would create a national ID card and a de facto national database – a concept that Congress rejected when it was first proposed several years ago.

The act would force states to produce standardized, tamper-resistant driver's licenses that would include machine-readable, encoded data. States wouldn't be required to comply. But those that don't comply would create hardship for residents, who wouldn't be able to use their licenses as official identification to travel on airplanes, collect federal benefits or gain access to federal buildings.

All drivers, including current license holders, would have to provide multiple documents to verify their identity before they could obtain a license or renew one. Drivers would have to provide several types of documentation, such as a photo ID, birth certificate, proof that their Social Security number is legitimate and something that verifies the applicant's full home address.

Some critics call the legislation anti-immigration because it would prohibit undocumented immigrants from obtaining a driver's license.

The law would compel DMV workers to verify the documents against federal databases and store the documents and a digital photo of the card holder in a database. Critics say the mandates would result in higher costs and longer lines at the DMV.

"It's a controversial measure and a controversial manner in which to pass it," Rotenberg said. "We want them to know that in passing (the Real ID Act), Congress mandated the collection of sensitive personal information by state DMVs at the same time that the state DMVs have become the target of attacks."

Since March, there have been at least three reported incidents of personal data being stolen for the sake of identity theft from DMV offices in Nevada, Florida and Maryland.

Senators opposing the act reluctantly passed it because it was slipped into a larger spending appropriations bill that authorized emergency funding for the Iraq war and tsunami victim relief.

Last month, 12 lawmakers – six Republicans and six Democrats – called on Senate Majority Leader Bill Frist (R-Tennessee) to prevent the ID bill from being slipped into other must-pass legislation. They asked Frist to refer the bill separately to the Senate Judiciary Committee, where it could receive a hearing and debate.

"Legislation in such a complex area without the benefit of hearings and expert testimony is a dubious exercise and one that subverts the Senate's deliberative process," the senators wrote in a letter to Frist.

Among the senators who signed the letter were Alexander, Durbin, John McCain (R-Arizona), Chuck Hagel (R-Nebraska), John Sununu (R-New Hampshire), Edward Kennedy (D-Massachusetts) and Richard Lugar (R-Indiana).

Rep. James Sensenbrenner (R-Wisconsin) wrote the Real ID Act and tried unsuccessfully to slip it into different must-pass legislation last year. But many lawmakers objected, which forced Sensenbrenner to try again this year.

Rotenberg said groups didn't mobilize strongly before the bill passed this week because they were hoping and expecting the Senate would keep the bill separate from other legislation to give it a proper hearing. Once it became clear last week that the Senate was not going to do this, there was little time to mobilize.

Jeff Lungren, spokesman for the House Judiciary Committee, which Sensenbrenner chairs, acknowledges that the bill wasn't debated on its own in the Senate, but he says the legislation was discussed extensively last year when Sensenbrenner first proposed placing it in another bill.

"We had plenty of debate," he said. "It started in September; it was in various committees of Congress. It was in the (9/11 bill) that the House passed (last October). It was the main bone of contention ... last year. It was also very much in the headlines in the news everywhere last November.... If some members (of Congress) chose not to deal with it (then) that's their fault."

Lungren said that senators told Sensenbrenner last year to put the provisions in a separate bill so they could consider the proposals.

"So we did that," Lungren said. "Nobody should be surprised or whine about lack of debate on these provisions."

Rotenberg disagrees.

"There were no hearings on the bill in the Congress, just a lot of procedural maneuvering," he said. "And how can he say that they agreed to allow the Senate to consider the bill separately when that is exactly what they prevented during the conference (where proponents pushed to have the bill inserted into the spending bill)?"

As for the idea that states might choose not to comply with the legislation, Lungren said they would "probably have some feedback from their residents if (residents) can't use their driver's license as a form of identification. But that's their call to make and we're hopeful they'll work with us to improve the security standards (of their cards)."

Lungren said the main standard put forth by the legislation regards verifying that people obtaining a state ID card are legally present in the state. He said 41 states currently have such requirements that meet the Real ID Act standard.

"It's the ... other states that have low standards," Lungren said. "Because of those low standards they put all Americans at risk."

President Bush is expected to sign the Iraq spending appropriations bill this week.