WASHINGTON — Justice Department lawyers showed ”poor judgment” but did not commit professional misconduct when they authorized CIA interrogators to use waterboarding and other harsh tactics at the height of the U.S. war on terrorism, an internal review released Friday found.

The decision closes the book on one of the major lingering investigations into the counterterrorism policies of George W. Bush’s administration. President Obama campaigned on abolishing the simulated drowning technique of waterboarding and other tactics that he called torture, but he left open the question of whether anyone would be punished for authorizing such methods.

An initial review by the Justice Department’s internal affairs unit found that former government lawyers Jay Bybee and John Yoo had committed professional misconduct, a conclusion that could have cost them their law licenses. But, underscoring just how controversial and legally thorny the memos have become, the Justice Department’s top career lawyer reviewed the matter and disagreed.

”This decision should not be viewed as an endorsement of the legal work that underlies those memoranda,” Assistant Deputy Attorney General David Margolis wrote in a memo released Friday.

Margolis, the top nonpolitical Justice Department lawyer and a veteran of several administrations, called the legal memos ”flawed” and said that, at every opportunity, they gave interrogators as much leeway as possible under U.S. torture laws. But he said Yoo and Bybee were not reckless and did not knowingly give incorrect advice, the standard for misconduct.

The Office of Professional Responsibility, led by another veteran career prosecutor, Mary Patrice Brown, disagreed.

”Situations of great stress, danger and fear do not relieve department attorneys of their duty to provide thorough, objective and candid legal advice, even if that advice is not what the client wants to hear,” her team wrote in a report that criticized the memos for a ”lack of thoroughness, objectivity and candor.”

The internal report also faulted then-Attorney General John Ashcroft and then-Criminal Division chief Michael Chertoff for not scrutinizing the memos and recognizing their flaws, but the report did not cite them for misconduct.

Yoo is now a law professor at the University of California, Berkeley, and Bybee is a federal judge on the 9th U.S. Circuit Court of Appeals based in San Francisco. The decision spares them any immediate sanctions, though state bar associations could independently take up the matter.

The memos authorized CIA interrogators to use waterboarding, keep detainees naked, hold them in painful standing positions and keep them in the cold for long periods of time. Other techniques included depriving them of solid food and slapping them. Sleep deprivation, prolonged shackling and threats to a detainee’s family were also used.