Nothing prepared Louisiana Gov. Kathleen Babineaux Blanco (D) or Mississippi Gov. Haley Barbour (R) for the devastation that descended on their states this week.

Facing what may be judged the worst natural disaster in the nation's history, the neighboring governors have struggled to organize huge emergency response operations that have initially overwhelmed available resources while trying to digest the scope of the physical and human damage that lies in Hurricane Katrina's wake.

After touring the damage along the Mississippi Gulf Coast on Tuesday that wiped out entire neighborhoods, destroyed 90 percent of the homes and buildings along the beachfront, and tossed floating casinos around like shoe boxes, Barbour likened the storm's force to a nuclear attack. "I can only imagine that this is what Hiroshima looked like 60 years ago," he told reporters.

Blanco, dealing with rising floodwater that has left most of New Orleans underwater and with the growing threat of human disaster and massive damage to the city's infrastructure, has faced if anything a far more daunting challenge of saving one of the United States' oldest and most cherished cities. "This whole situation is totally overwhelming," she said on ABC's "Good Morning America" yesterday.

The storm has put a spotlight on two first-term executives who were elected within weeks of each other in November 2003, but who have markedly different personal histories and political styles.

Barbour, 57, is a well-connected politician who spent two decades in Washington before returning to his home state to run for governor. He is a former Republican National Committee chairman, was White House political director during the Reagan administration and was one of the capital's most successful lobbyists before winning election.

Blanco, 62, is a former school teacher who rose through the ranks of state government to become the first female governor of Louisiana. She served as a state representative for five years, was a member of the Public Service Commission and spent two terms as lieutenant governor. Her come-from-behind victory in the gubernatorial runoff in 2003, which proved her critics wrong, provided Democrats a rare bright spot in the South.

The cleanup from Katrina is now a national emergency, with President Bush back in Washington to oversee relief efforts and the Department of Homeland Security tasked with leading a federal response that includes actions by agencies across the executive branch. But for Blanco and Barbour -- and to a lesser extent Alabama Gov. Bob Riley (R), whose state took a lesser hit on Monday -- the storm will define and dominate their public lives for the duration of their time in office.

"Governors tend to be the focal point at the time of a disaster, as they should be," said Joe M. Allbaugh, director of the Federal Emergency Management Agency during Bush's first term. He added: "The governors' principal role is to make sure all the assets available to him or her are fully deployed."

Speaking by telephone from Louisiana, where he is helping coordinate the private-sector response to the storm, Allbaugh said Katrina has left behind a situation that evokes the destruction of Sept. 11, 2001, though without as much loss of life. "It is unreal," he said. "When you see the pictures on television, it really cannot do the devastation and the damage justice."

"They're both doing a fantastic job of dealing with a truly impossible situation," said Arkansas Gov. Mike Huckabee (R), chairman of the National Governors Association, of Blanco and Barbour. Describing New Orleans as "virtually the lost city of Atlantis," Huckabee said Blanco may face the more difficult long-term challenge, given what he said is likely to be extensive damage to roads, bridges, buildings and homes from being submerged for what could be weeks.

Both governors -- like other leaders in times of public crisis -- are working to project the right combination of empathy for the stricken and efficiency in managing the emergency, according to associates.

"She's a person with a lot of experience," said former Louisiana senator John Breaux (D). "She's obviously affected tremendously by the emotional impact of the devastation. I think she's doing everything humanly possible to bring it together."

Asked whether Blanco sounded discouraged by the size of the disaster that has hit her state, Breaux said: "No, I think she was on top of it. But considering the circumstances, with a whole city underwater, it's hard to be calm, cool and collected."

Barbour combines a good-old-boy persona with a shrewd sense of politics and a deep interest in policy. Typically upbeat, he has sought to rally his state with assurances that Mississippi will rebuild bigger and better than ever. But as the storm approached, he could not disguise his sense of concern.

Hours before the storm hit, he was on the telephone with Ed Rogers, a friend. "He was dealing with the reality that he was ground zero," Rogers recalled yesterday. Barbour sounded terse and focused, Rogers said. "He's been my best friend [for three decades]," he added. "He said, 'Pray for us.' He's never said that to me before."

From left, New Orleans Mayor C. Ray Nagin confers with Louisiana Gov. Kathleen Blanco, National Guard Maj. Gen. Bennett Landreneau and Air National Guard Brig. Gen. Brod Veillon. Mississippi Gov. Haley Barbour asked a friend for prayers.