Washington ? The White House and Homeland Security chief Michael Chertoff failed to provide decisive action when Hurricane Katrina struck, congressional investigators said Wednesday in a stinging assessment of slow federal relief efforts.

The White House had no clear chain of command in place, investigators with the Government Accountability Office said, laying much of the blame on President Bush for not designating a single official to coordinate federal decision-making for the Aug. 29 storm. Bush has accepted responsibility for the government’s halting response, but for the most part then-FEMA Director Michael Brown, who quit days after the hurricane hit, has been the public face of the failures.

“That’s up to the president of the United States,” GAO Comptroller General David M. Walker told reporters after being asked whether Chertoff should have been the lead official during the emergency.