WASHINGTON For days, as an oil spill spread in the Gulf of Mexico, BP assured the government the plume was manageable, not catastrophic. Federal authorities were content to let the company handle the mess while keeping an eye on the operation.

But then government scientists realized the leak was five times larger than they had been led to believe, and days of lulling statistics and reassuring words gave way Thursday to an all-hands-on-deck emergency response. Now questions are sure to be raised about a self-policing system that trusted a commercial operator to take care of its own mishap even as it grew into a menace imperiling Gulf Coast nature and livelihoods from Florida to Texas.

The pivot point had come Wednesday night, at a news conference at an oil research center in the tiny community of Robert, La. That's when the nation learned the earlier estimates were way off, and an additional leak had been found.

On Thursday, President Barack Obama set in motion a larger federal mobilization, pledging to deploy "every single available resource" to the area and ordering his disaster and environmental leaders to get down there in person. Only a few days after the Coast Guard assured the country there was "ample time" to protect the coast if oil came ashore, warnings from the government were newly alarming.

"I am frightened for the country, for the environment," said David Kennedy, assistant chief of the National Ocean Service at the National Oceanic and Atmospheric Administration. "This is a very, very big thing, and the efforts that are going to be required to do anything about it, especially if it continues on, are just mind-boggling."

The political subtext of the crisis was clear and increasingly on people's minds, whether from a federal office deploying oil-containment booms or from a Louisiana parish awaiting yet another sucker punch from the sea.

Will this be Obama's Katrina? Should the federal and state governments have done more, and earlier? Did they learn the lessons of the devastating hurricane?

Political calculations vied with the increasingly scary Gulf reality - hundreds of thousands of gallons of oil and its progression to landfall as soon as Thursday night. Florida Gov. Charlie Crist, who also is in a hot campaign for the Senate, flew over the slick and commended the federal actions to date but wondered if anyone, really, could be doing enough in this situation. "It appeared to me," he said, "that this is probably much bigger than we can fathom."

The crisis began with a massive explosion aboard the drilling rig Deepwater Horizon on April 20, more than 40 miles off the Louisiana coast. The search for 11 missing workers overshadowed environmental concerns until they were given up for lost.

Rear Adm. Mary Landry, chief of the Coast Guard in the region, said at the outset that most of the oil was burning off, leaving only a moderate rainbow sheen on the water and no sign of a major spill.

"Both the industry and the Coast Guard have technical experts actively at work," she said. "So there's a whole technical team on both sides of the aisle here to ensure we keep the conditions stable."