The 45-55 vote came after several days of debate over the controversial military detainee issue included in the pending Department of Defense Authorization bill for Fiscal Year 2012. That bill includes a provision penned by leaders of the Senate Armed Services Committee Carl LevinCarl Milton LevinDemocrats: A moment in history, use it wisely America's divide widens: Ignore it no longer Senator Tom Coburn's government oversight legacy MORE (D-Mich.) and John McCainJohn Sidney McCain Senate outlook slides for GOP Juan Williams: Time for boldness from Biden Democrats lead in three battleground Senate races: poll MORE (R-Ariz.) that would encourage military rather than civilian detention for individuals captured at home who the executive branch suspects  of colluding with the enemy.

Sen. Dianne FeinsteinDianne Emiel FeinsteinBottom line Filibuster reform gains steam with Democrats Senate panel votes 21-1 to back Justice IG measure over Graham objections MORE (D-Calif.), the author of the amendment, touted the fact that it consisted of simply adding the word "abroad" to the underlying provision, thus ensuring that individuals captured within the U.S. are granted a lawyer, Miranda rights and a civilian trial. 

Throughout the day Feinstein argued on principle, stating that a civilian trial is part of the American identity enshrined in the Constitution. She also argued that the civilian courts are better equipped and have a better record of prosecuting terrorists than military tribunals. 


But from the right several conservative senators, including Kelly AyotteKelly Ann AyotteBottom line Bottom line Bottom Line MORE (R-N.H.) argued that since the war on terror is partially waged on the home front, the rules of war ought to apply on native soil. 

"This amendment would lead to an absurd result where if you make it to our soil, like the 9/11 terrorist did, you cannot be held in military custody," said Ayotte. "[W]e are laying out a welcome mat to say if you make it in America you wont be held in custody."

President Obama, meanwhile, also opposes the detainee language included in the underlying legislation and has hinted he will veto it if it is not amendended before it clears the Senate later on Thursday.