Bush’s backing for the congressional inquiry raised the possibility that lawmakers might expand presidential authority to:

• Order mandatory civilian evacuations

• Dispatch U.S.-based armed forces for emergency search-and-rescue operations

• Grant wider leeway for active-duty U.S. military personnel to carry out law enforcement operations.

“It’s really important that as we take a step back and learn lessons — that we are in a position to adequately answer the question: ‘Are we prepared for major catastrophes?”’ Bush said during a tour of hurricane damage in New Orleans.

He said if there was a terrorist attack with weapons of mass destruction, such as germ-warfare agents, “we’ve got to make sure we understand the lessons learned to be able to deal with catastrophe.”

Asked whether the federal government needed broader authority to “come in earlier or even in advance of a storm that (is) threatening?” Bush replied: “I think that’s one of the interesting issues that Congress needs to take a look at.”

Bush’s comments came as outside experts urged a variety of changes they said could improve the federal government’s ability to respond to natural disasters or terrorist attacks.

Richard A. Falkenrath, a former homeland security adviser at the White House during Bush’s first term, said officials “need to look very, very closely” at expanding presidential authority to override “a delayed and ineffective evacuation order at the state and local level” that he said had occurred before the hurricane.

“It’s entirely possible we would need such authority in a biological weapons attack and the destruction of a chlorine tanker and nuclear weapons attack, where local and state capabilities would be instantaneously overwhelmed, and so it would be good to get this one sorted out,” said Falkenrath, now a scholar at the Brookings Institution.

Michael O’Hanlon, a national security scholar at Brookings, said the White House ought to create an emergency response team within the armed forces that could be rushed to disasters “where every hour counts.”

O’Hanlon said it had taken too long to get Navy and Air Force helicopters into the New Orleans area to assist early search-and-rescue operations by police and the U.S. Coast Guard.