Adm. Thad Allen: "The enemy is coming ashore."

Hours before the president's press conference, an ominous plume of oil six miles wide and 22 miles long was discovered snaking its way toward Mobile Bay from BP's wellhead next to the wreckage of its Deepwater Horizon rig. Admiral Thad Allen, the U.S. commander overseeing the cleanup, framed the spill explicitly as an invasion: "The enemy is coming ashore," he said. Louisiana beaches were assaulted by blobs of oil that began to seep beneath the sand; acres of marshland at the "Bird's Foot," where the Mississippi meets the Gulf, were befouled by shit-brown crude – a death sentence for wetlands that serve as the cradle for much of the region's vital marine life. By the time Obama spoke, it was increasingly evident that this was not merely an ecological disaster. It was the most devastating assault on American soil since 9/11.

Like the attacks by Al Qaeda, the disaster in the Gulf was preceded by ample warnings – yet the administration had ignored them. Instead of cracking down on MMS, as he had vowed to do even before taking office, Obama left in place many of the top officials who oversaw the agency's culture of corruption. He permitted it to rubber-stamp dangerous drilling operations by BP – a firm with the worst safety record of any oil company – with virtually no environmental safeguards, using industry-friendly regulations drafted during the Bush years. He calibrated his response to the Gulf spill based on flawed and misleading estimates from BP – and then deployed his top aides to lowball the flow rate at a laughable 5,000 barrels a day, long after the best science made clear this catastrophe would eclipse the Exxon Valdez.

Hours after BP’s rig sank on April 22nd, a white board in NOAA's "war room" in Seattle displays the administration's initial, worst-case estimate of the spill — 64,000 to 110,000 barrels a day.

Even after the president's press conference, Rolling Stone has learned, the administration knew the spill could be far worse than its "best estimate" acknowledged. That same day, the president's Flow Rate Technical Group – a team of scientists charged with establishing the gusher's output – announced a new estimate of 12,000 to 25,000 barrels, based on calculations from video of the plume. In fact, according to interviews with team members and scientists familiar with its work, that figure represents the plume group's minimum estimate. The upper range was not included in their report because scientists analyzing the flow were unable to reach a consensus on how bad it could be. "The upper bound from the plume group, if it had come out, is very high," says Timothy Crone, a marine geophysicist at Columbia University who has consulted with the government's team. "That's why they had resistance internally. We're talking 100,000 barrels a day."

The median figure for Crone's independent calculations is 55,000 barrels a day – the equivalent of an Exxon Valdez every five days.