As New Orleans descended into chaos last week and Louisiana's governor asked for 40,000 soldiers, President Bush's senior advisers debated whether the president should speed the arrival of active-duty troops by seizing control of the hurricane relief mission from the governor.

For reasons of practicality and politics, officials at the Justice Department and the Pentagon, and then at the White House, decided not to urge Mr. Bush to take command of the effort. Instead, the Washington officials decided to rely on the growing number of National Guard personnel flowing into Louisiana, who were under Gov. Kathleen Babineaux Blanco's control.

Aides to Ms. Blanco said she was prepared to accept the deployment of active-duty military officials in her state. But she and other state officials balked at giving up control of the Guard as Justice Department officials said would have been required by the Insurrection Act if those combat troops were to be sent in before order was restored.

In a separate discussion last weekend, the governor also rejected a more modest proposal for a hybrid command structure in which both the Guard and active-duty troops would be under the command of an active-duty, three-star general - but only after he had been sworn into the Louisiana National Guard.

The debate began after officials realized that Hurricane Katrina had exposed a critical flaw in the national disaster response plans created after the Sept. 11 attacks. According to the administration's senior domestic security officials, the plan failed to recognize that local police, fire and medical personnel might be incapacitated.

While combat troops can conduct relief missions without the legal authority of the Insurrection Act, Pentagon and military officials say that no active-duty forces could have been sent into the chaos of New Orleans on Wednesday or Thursday without confronting law-and-order challenges.

On the issue of whether the military could be deployed without the invitation of state officials, the Office of Legal Counsel, the unit within the Justice Department that provides legal advice to federal agencies, concluded that the federal government had authority to move in even over the objection of local officials.

This act was last invoked in 1992 for the Los Angeles riots, but at the request of Gov. Pete Wilson of California, and has not been invoked over a governor's objections since the civil rights era - and before that, to the time of the Civil War, administration officials said. Bush administration, Pentagon and senior military officials warned that such an extreme measure would have serious legal and political implications.

But just as important to the administration were worries about the message that would have been sent by a president ousting a Southern governor of another party from command of her National Guard, according to administration, Pentagon and Justice Department officials.

"Can you imagine how it would have been perceived if a president of the United States of one party had pre-emptively taken from the female governor of another party the command and control of her forces, unless the security situation made it completely clear that she was unable to effectively execute her command authority and that lawlessness was the inevitable result?" asked one senior administration official, who spoke anonymously because the talks were confidential.

Officials from the Department of Homeland Security say the experience with Hurricane Katrina has demonstrated flaws in the nation's plans to handle disaster.

"This event has exposed, perhaps ultimately to our benefit, a deficiency in terms of replacing first responders who tragically may be the first casualties," Paul McHale, the assistant secretary of defense for domestic security, said.

Michael Chertoff, the secretary of homeland security, has suggested that active-duty troops be trained and equipped to intervene if front-line emergency personnel are stricken. But the Pentagon's leadership remains unconvinced that this plan is sound, suggesting instead that the national emergency response plans be revised to draw reinforcements initially from civilian police, firefighters, medical personnel and hazardous-waste experts in other states not affected by a disaster.

The federal government rewrote its national emergency response plan after the Sept. 11 attacks, but it relied on local officials to manage any crisis in its opening days. But Hurricane Katrina overwhelmed local "first responders," including civilian police and the National Guard.