SAN DIEGO — Oprah giveth, and Oprah taketh away.

In the 2000 presidential campaign, George W. Bush won the all-important Oprah primary. Al Gore had appeared on Oprah Winfrey's show a few days before Bush, and Gore came off as stiff by failing to greet Oprah with a kiss on the cheek. Bush was careful not to make the same mistake. He kissed the mighty Oprah.

Now, with a majority of Americans telling pollsters that they think the administration's response to Hurricane Katrina was slow and inadequate — even while most of them say that no one is to blame for the disaster itself — there is little doubt that President Bush is facing the toughest challenge to his presidency.

It's a challenge more difficult than 9/11, where at least Bush had the benefit of being able to grab a bullhorn and channel the nation's anger at some external force, i.e. "the people who knocked these buildings down." How do you get the American people fired up over a hurricane that has come and gone?

People along the Gulf Coast are angry — but not at Katrina. They're angry at their government and how it so obviously failed those it is supposed to serve.

As Bush struggles to deal with the aftermath of Katrina — both personally and politically — even his supporters are saying that he's failing miserably.

And guess who is one of the people handing out the report cards? It's Oprah, who has taken on relief efforts for Katrina as a personal crusade and who — like those countless Americans volunteering at shelters, dropping off blankets and diapers and bottled water, making cash donations — could teach FEMA a thing or two about putting results before red tape.

While the bureaucrats in Baton Rogue and Washington were still pointing fingers, the media mogul dispatched 33 trucks filled with food, water and supplies to aid the victims of Katrina and pulled together her own network of celebrity "angels" — John Travolta, Kelly Preston, Lisa Marie Presley, Julia Roberts — to do likewise, or to simply show up at shelters and give moral support to people who thought they had been forgotten.

Winfrey spent last week broadcasting from the impacted area — and lobbing grenades at the administration. Speaking with a young woman in Mississippi who had — in a phrase you hear over and over again in this tragedy — lost everything, Winfrey asked: "Do you feel like you've been abandoned?" The young woman said that, yes, as a matter of fact she did. Winfrey told her that she wasn't alone and that she had interviewed so many people who had just one simple and haunting question: "Where is our government?"

I could almost hear what's left of Bush's approval rating fall through the floor.

That's because, more than tax cuts or education reform or prescription-drug credits, this is what presidents are for. They take charge in times of crisis. They offer compassion and strength to the suffering. They protect the lives of their people. They don't point fingers or tolerate it when underlings do. They make sure that, as Harry Truman said, the buck stops here.

Presidents act decisively and firmly, sending whatever resources need to be sent as quickly as they need to be sent and firing whichever incompetent pencil pusher deserves to be fired. Not later, as the president would seem to prefer, when the media spotlight has dimmed — but now, when it matters, when you have a chance to get rid of people like FEMA Director Michael Brown and Homeland Security Secretary Michael Chertoff, who don't seem to know what they're doing or how to respond to criticism, and put in people who might know better what to do.

Surely there must be some four-star general in Iraq who's eager for a change of scenery. If he started handing out pink slips, Bush would send the message that his is an administration that knows how to admit its mistakes and correct them, if not in the Persian Gulf at least on the Gulf Coast.

Rule No. 1: People come before politics. Oprah Winfrey — and countless volunteers and humanitarians across the country — understand that. But nearly two weeks after Katrina began her rampage, it's still not clear that Bush does.