By Susan Cornwell
WASHINGTON (Reuters) - The Senate on Thursday voted in favor of a requirement that captured terrorism suspects, including those detained in the United States, be held in military custody.
The proposed legislation mandates that suspected members of al Qaeda and other militant groups be detained by the U.S. military instead of the U.S. criminal court system. American citizens, however, are exempted from the mandatory military detention requirement.
The Democratic-controlled Senate voted 55-45 to reject an attempt by Senator Dianne Feinstein to limit the military custody requirement to suspects captured outside the United States.
The detainee provisions, which are opposed by the Obama administration, are part of a defense bill that is expected to pass the Senate on Thursday or Friday. The House of Representatives has passed similar legislation.
Once differences in the legislation are worked out, the bill will be sent to President Barack Obama, who has threatened to veto it.
The debate is part of a long battle between Obama, a Democrat, and some lawmakers over whether terror suspects should be prosecuted as "enemy combatants" before military commissions, or as criminal suspects in federal courts.
The Obama administration has sought to prosecute terror suspects in civilian as well as military courts.
Republicans and some Democrats have urged that only military courts be used, and Congress repeatedly has voted to limit transfers of detainees from the U.S. military prison at Guantanamo Bay, Cuba, to the United States.
Defense Secretary Leon Panetta and FBI director Robert Mueller, as well as intelligence officials, have written to Congress to express their opposition to mandatory military custody for terrorism suspects.
The legislation contains waiver provisions giving the executive branch the right to place a prisoner in the U.S. criminal court system if it is in the interest of national security.
Law enforcement officials, including Mueller, have argued that this procedure is too awkward, noting the waiver has to come from the U.S. defense secretary in consultation with the secretary of state and the director of national intelligence, presumably while an investigation is ongoing.
Feinstein, who chairs the Senate Intelligence Committee, argued against the proposed strictures on handling of terror suspects, noting that ordinary criminal courts had produced lengthy sentences for convicted terror suspects.
"I just had a hard time, knowing, why if it's not broke, we need to fix it," she said.
But Republican Senator Kelly Ayotte warned al Qaeda might send others to attack the United States if it thought that suspects captured on U.S. soil would not go into military custody.
"In our country we need the authority in the first instance to hold those individuals in military custody," she said.
Otherwise, "we're laying out a welcome mat, to say, that if you make it to America, you won't be held in military custody," Ayotte said.
Jeh Johnson, Defense Department general counsel, said on Thursday the detainee provisions would actually hinder the pursuit of terrorism suspects.
"Al Qaeda is a more decentralized organization than it was 10 years ago and that the threat will continue to evolve in ways that we can't entirely anticipate ... we urge our friends in Congress to not take away our counterterrorism options," Johnson said at an American Bar Association conference.
(Additional reporting by Tabassum Zakaria; Editing by Missy Ryan and Paul Simao)