Nonetheless, the Obama administration has asserted that a congressional resolution authorizing force against al Qaeda gives the president the right to detain, kill and abduct suspected terrorists all over the world.
In addition, Mr. Obama threatened to veto an amendment to the Intelligence Authorization bill for 2011 if it contained a provision that requires the full intelligence committee, instead of its chairman and ranking member, to be informed about covert action.
Sen. Christopher S. Bond, Missouri Republican and vice chairman of the Senate intelligence committee, said Mr. Obama has hampered the CIA in some areas by delegating more counterterrorism authority to the Justice Department.
But Mr. Bond also acknowledged similarities with the Bush administration.
“I appreciate his administration supporting the state secrets doctrine in court proceedings,” he said. “It is important that people not be allowed to get military and intelligence secrets through a lawsuit. That is important. There are other policies which he has continued, some of them I cannot speak officially about, but they have been effective in taking out terrorists in the Pakistani areas.”
Fran Townsend, a former homeland security adviser to Mr. Bush, said: “On counterterrorism policy, they found they agree with much of what we did, but that fact is politically inconvenient to acknowledge.”
An ACLU report issued in July found: “On a range of issues including accountability for torture, detention of terrorism suspects, and use of lethal force against civilians, there is a very real danger that the Obama administration will enshrine permanently within the law policies and practices that were widely considered extreme and unlawful during the Bush administration.”
The continuities also extend to homeland security.
“From a homeland security point of view, the points of continuity are striking and the points of departure are minor,” said Stewart Baker, a former policy chief for the Department of Homeland Security and author of “Skating on Stilts,” a legal defense of much of the new policies in the global war on terror.
“The Obama administration is, if anything, even more enthusiastic about using travel information to identify potentially risky travelers,” he said. “They are actually more aggressive about the use of the ‘no-fly’ list than the last administration, after the Christmas Day bombing incident.”
In one of the most significant areas of continuity, the Obama administration also has largely based much of its war authorities on the Sept. 14, 2001, congressional resolution authorizing the use of military force against the individuals and groups responsible for the Sept. 11 attacks: the Authorization for Use of Military Force, known as the AUMF.
Obama administration lawyers have argued the AUMF gives the government the authority to detain terrorism suspects indefinitely and conduct targeted killings in countries where the United States has not declared war.
Jack Goldsmith, a former head of the Justice Department’s office of legal counsel who rolled back some of the legal justifications for Bush-era enhanced interrogation, said: “The AUMF is the main font of authority for both detention and targeting activities in Afghanistan and for Somalia and Yemen. That was also the main font of authority for the Bush administration.”
The continuity also extends to the federal government’s surveillance powers.