Although Barack Obama campaigned on the promise to break with many of George W. Bush ’s national security policies and pledged to work more closely with Congress on issues such as Guantánamo, that has not translated into an apparent readiness to make Congress an equal partner in that area.

On the contrary, the Obama administration has largely clung to Bush-era executive powers on the Guantánamo Bay detention center — and in at least two other areas. For instance, the White House has moved to head off new legislation that would curb the use of the state secrets privilege to keep executive branch documents from being examined in court. And it is pushing Congress to reauthorize expiring provisions of the anti-terrorism law (PL 109-177) known as the Patriot Act, with as few new restrictions as possible on the government’s statutory authority.

To be sure, the Obama administration has adopted a more conciliatory style and has taken some steps to unwind Bush-era policies. It is actively working to close Guantánamo, even though Congress continues to balk at all of the options floated as places for transferring the detainees. The Justice Department has issued a new policy to limit the assertion of the state secrets privilege. And the administration has pledged to keep an open mind with lawmakers rewriting parts of the Patriot Act.

But on all those questions, the White House has given little legal ground; technically, those policy changes are voluntary. One reason may be that Obama, as president, now has the constitutional responsibility to protect presidential prerogatives.

“Presidents and their lawyers are aware that they are protecting not just the administration, but the institution of the presidency,” said Peter M. Shane, an Ohio State University law professor. He said that the president “may be reluctant to impose what he takes to be his views on the institution of the presidency for all time.”

The White House argues that the broad use-of-force authorization Congress granted the president within a week of the Sept. 11 terrorist attacks gives Obama all the authority he needs to arrest and imprison suspected terrorists. That’s a change from the Bush administration, which had argued that the president’s constitutional authority as commander in chief — not any act of Congress — empowered him to hold detainees.

But it is also at odds with Obama’s declaration, in a May speech at the National Archives, that going forward, “my administration will work with Congress to develop an appropriate legal regime” for such detentions.

Detention and the Law

One consequence of not seeking legislation to set a framework for indefinite detention is that it leaves the question in the hands of the courts, which have been weighing a raft of legal challenges by Guantánamo detainees.

Sen. Lindsey Graham , R-S.C., who favors new legislation, says the administration should work with Congress to develop a legal regime for preventative detention. “I think the ghost of the Bush administration is beginning to haunt the White House,” he said. The administration should involve Congress in part so that if a released suspect someday launches a terrorist attack, lawmakers will share in the blame. “The administration shouldn’t own this by themselves,” he said.

The administration has also moved to hold Congress at arm’s length on other issues related to the scope of executive authority. For instance, Obama’s Justice Department has invoked the state secrets privilege in several lawsuits challenging the legality of Bush’s surveillance and detention policies — echoing Bush’s own frequent invocation of the privilege. And Democrats in the House and Senate have introduced legislation to circumscribe that legal defense.

A bill by Senate Judiciary Chairman Patrick J. Leahy , D-Vt., would require the government to release unclassified affidavits in such cases. Under his approach, a federal judge would have to examine the material, or at least a “sufficient sampling” of it, to determine whether the executive branch was properly invoking the privilege. If the court decided the state secrets claim was valid, it could still order the government to turn over a summary of the privileged information, redacted material or another alternative.

Rep. Jerrold Nadler , D-N.Y., has introduced similar legislation in the House, but neither measure has seen a full committee markup.