President Obama used the last day of 2011 to sign the defense authorization bill, formally ending weeks of heated debate in Congress and intense lobbying by the administration. Obama’s main justification is found in his signing statement: I have signed the Act chiefly because it authorizes funding for the defense of the United States and its interests abroad, crucial services for service members and their families, and vital national security programs that must be renewed. Yet many have decried the bill’s language that would allow indefinite detention for suspected terrorists without a trial–including Americans arrested in the United States. Among those…