“Nobody likes to have a feeling that you can’t do something about a very big problem”

Mr. Obama said he would hold both the government and BP accountable. But he did not retreat from his plan to expand offshore oil drilling and in fact portrayed the commission as a means to make that possible.

“Because it represents 30 percent of our oil production, the Gulf of Mexico can play an important part in securing our energy future,” the president said. “But we can only pursue offshore oil drilling if we have assurances that a disaster like the BP oil spill will not happen again.”

Adm. Allen rejected the notion of a too-cozy relationship between the government and BP, saying the government was closely overseeing the company’s efforts.

Asked on CNN whether he trusted BP, the admiral referred to the company’s chief executive, saying: “I trust Tony Hayward. When I talk to him, I get an answer.” But he took exception with Mr. Hayward’s comment, in an interview with Sky News in Britain, that the environmental impact of the leak was likely to be “very, very modest.”

The admiral said that it would be wrong to suggest that the problem was anything short of “potentially catastrophic for this country.”

The accident has put some advocates of offshore drilling in an awkward position. But the woman who brought the phrase “Drill, baby, drill” into the political lexicon, the former Alaska Governor Sarah Palin, insisted on Sunday that her views had not changed.

“I’m a supporter of offshore drilling,” she said on Fox News Sunday, while adding that “the oil companies have got to be held accountable.” But Mrs. Palin suggested that oil-company donations to Mr. Obama’s presidential campaign might help explain why it took him “so doggone long,” in her view, to respond to the spill.

Mr. Obama has come under increasing fire for not being more aggressive. Cable channels were filled with commentators asking why the federal government had left so much to BP to handle, and similar complaints were heard by residents along the Gulf Coast.

Adm. Allen said that he understands their deep discontent. “Nobody likes to have a feeling that you can’t do something about a very big problem,” said the admiral, who helped lead the recovery effort after Hurricane Katrina.

But “we’re on entirely new ground here,” he said on CNN. “This is an entirely new world.”