An adroit Republican parliamentary maneuver ultimately sank the bill. GOP leaders offered a motion that would have sent it back to the House intelligence and Judiciary committees with a requirement that they add language specifying that nothing in the measure would apply to surveilling the communications of bin Laden, al-Qaeda or other foreign terrorist organizations.

Approval of the motion would have restarted the legislative process, effectively killing the measure by delay. Democratic leaders scrambled to persuade their members to oppose it, but with Republicans accusing Democrats of being weak on terrorism, a "no" vote proved too hard to sell, and so the bill was pulled from the floor.

Stacey Bernards, a spokeswoman for House Majority Leader Steny H. Hoyer (D-Md.), called the Republican maneuver "a cheap shot, totally political."

Caroline Fredrickson, director of the Washington legislative office of the American Civil Liberties Union, called it a "perfect storm" of progressive Democrats who did not think the bill protected basic constitutional rights and of Republicans who took advantage of the lack of unity. "It was too precipitous a process, and it ended up in a train wreck," she said. "It was total meltdown."