This was a crucial procedural vote forced by Republicans to require three-fifths of the Senate - the number of Senators required to invoke cloture and thus end debate - to agree to proceed with a measure that would have restored the right of habeas corpus to individuals deemed "enemy combatants" by the Bush administration in the so-called "war on terror." Proposed by Sens. Arlen Specter (R-Pa.) and Patrick Leahy (D-Vt.) as an amendment to legislation setting policy for the Defense Department for fiscal 2008, the language would have revoked the suspension of habeas corpus Congress instituted in 2006.

The right of habeas corpus is a legal instrument outlined in the Constitution that allows prisoners to seek redress for what they believe to be unlawful confinement. It is widely seen by legal scholars as the most fundamental safeguard of individual freedom against arbitrary state action. In practice, it means that the government has to show cause for holding someone against his or her will.

Many Progressives and civil libertarians believe the suspension of habeas corpus to be unconstitutional, while many Republicans believe the "war on terror" is just the sort of exceptional circumstance the Constitution allows.

Instead of sending terrorist suspects through the U.S. justice system, the Bush administration opted to set up military tribunals with dramatically curtailed rights for the accused, including no right to habeas corpus. The Supreme Court ruled in June 2006 that the administration's military tribunals violated both domestic and international law. Following that decision, Congress retroactively approved the suspension of habeas corpus by statute in late 2006.

Specter and Leahy maintained that the revocation was unconstitutional and a gross abdication of the country's responsibility to human rights and due process. Congress, they said, cannot legislate away a constitutional right.

"The constitutional right of habeas corpus is expressly recognized in the Constitution, with a provision that habeas corpus may be suspended only in time of invasion or insurrection, neither of which situation is present here," Specter said. "That fundamental right has been in existence since the Magna Carta in 1215."

Many other Republicans countered that Specter and Leahy's amendment amounted to a "terrorist bill of rights."

Sen. Lindsey Graham (R-S.C.) asserted that the language would allow enemy prisoners to go to a federal court of their choosing to bring lawsuits against the government, which he said was "something never granted to any other prisoner in any other war."

"To start that process now would be an absolute disaster for this country and has never been done before and should not be done now," Graham continued.

Specter countered that Graham's arguments were "outdated," given the Supreme Court's 2006 decision. He said the legal rights afforded to detainees in the military tribunals were "palpably deficient and obviously inadequate."

This motion to invoke cloture was necessary because Republicans threatened to use parliamentary procedures to prevent the amendment from coming to a vote. Cloture is the only procedure in the Senate that restricts the amount of time a bill may be considered. Successfully invoking cloture means that the measure under consideration will be brought to a vote. Otherwise, one Senator could hold up the legislation by refusing to yield the floor, an act known as a filibuster. Under Senate rules, cloture requires three-fifths of the chamber, normally 60 votes.

Specter and Leahy did not have the 60 votes necessary to invoke cloture, and the motion failed even though it received a majority of the Senate. The final vote was 56 to 43. Democrats were unanimous in their support, and they were joined by six Republicans, but it was not enough. Thus, an amendment to a defense policy bill to reinstate the right of habeas corpus for detainees held by the United States failed, leaving individuals held in U.S. detention facilities without the right to see the evidence against them.