Analysis: This is President Bush's biggest political crisis, writes Denis Staunton in New Orleans.
As the last survivors leave New Orleans and the grim harvest of the dead gets under way, Hurricane Katrina is directing her fury towards George W Bush's presidency. The disaster has created Mr Bush's biggest political crisis since he took office and has cast a harsh spotlight on the issues of race and class that many US politicians prefer to keep in the shadows.
The White House has torn up the president's timetable for this week, cancelling a visit from China's president and announcing that Mr Bush will return to Louisiana and Mississippi today.
But as public anger focuses on the administration's failure to act quickly in New Orleans, Mr Bush may face fresh difficulties in pursuing his most cherished policy objectives, such as reforming the pensions system, abolishing inheritance tax and keeping US soldiers in Iraq.
Mr Bush was unpopular before the hurricane struck and most Americans now believe that his decision to invade Iraq was a mistake.
His failure to take immediate command of the rescue operation last week has left him looking weak, out of touch and lacking authority.
The conservative commentator, David Brooks, described last week's events as an "anti-9/11" in their impact on public confidence in institutions.
"I think it is a huge reaction we are about to see. I mean, first of all, they violated the social fabric, which is in the moments of crisis you take care of the poor first. That didn't happen; it's like leaving wounded on the battlefield," he told Jim Lehrer's NewsHour.
Mr Bush's slow response to the disaster suggests a failure to grasp both the scale of the tragedy in New Orleans and the shame many Americans felt at the spectacle of dead bodies floating in a US city for five days while thousands of desperate people remained stranded.
The fact that most of the victims were poor African-Americans reinforced a suspicion that this administration is indifferent to the suffering of those without influence.
Columnist Maureen Dowd wrote in the New York Times: "When the president and vice-president rashly shook off our allies and our respect for international law to pursue a war built on lies, when they sanctioned torture, they shook the faith of the world in American ideals.
"When they were deaf for so long to the horrific misery and cries for help of the victims in New Orleans - most of them poor and black, like those stuck at the back of the evacuation line yesterday while 700 guests and employees of the Hyatt Hotel were bused out first - they shook the faith of all Americans in American ideals."
Two out of three residents of New Orleans are African-American and the city's poverty rate is twice the national average, with more than 40 per cent of its children living in poverty, according to statistics from the US government.
Preparing for the hurricane, the authorities did not consider that more than one-fifth of the city's population had no car and that many were too ill to escape without help.
Almost one in three of Louisiana's and Mississippi's National Guard were serving in Iraq last week when they were needed urgently at home to stop the murder, rape and looting that followed the hurricane.
The drama in New Orleans will move into a bleak new act this week as the dead are counted and the true scale of the disaster becomes clear.
For Mr Bush, the coming days will be crucial in determining if he is remembered as the president who united his nation after the murderous attacks on 9/11, or as a reckless leader who failed his most vulnerable citizens in their hour of greatest need.