The Obama administration lagged in its initial response to the BP oil spill, played down spill projections, ultimately overreacted, and injected politics into the spill response, according to a report by President Obama's own oil spill commission.

For close watchers of the oil spill – including millions of Americans, especially on the Gulf Coast – the preliminary findings of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling are hardly surprising, given the wall-to-wall coverage of and commentary about the almost three-month-long ordeal. Some 4.4 million barrels of oil (or about 184 million gallons) of light Louisiana crude spewed into the Gulf of Mexico before the Macondo well was capped on July 15.

The White House on Wednesday pushed back against the commission's assertion that the administration response was either not competent or "not fully candid" with the American people. The National Oceanic and Atmospheric Administration, tasked with assessing the damage, said in a statement, "The facts bear out that the federal response significantly mitigated the impact of the spill."

The report, to be submitted in final form at year's end, may ultimately prove embarrassing or politically damaging for the White House. Yet the late-in-the-game transparency, added to the "fog of war" considerations of the early days of the spill, may yet stand as a candid moment of reflection for a young White House and the agency chiefs who responded to what became the worst commercial oil spill in US history. The report also suggests there is a need to clarify the "national incident" command structure for the public – and for the government itself.

"The oil spill was nowhere near 'Obama's Katrina,' as many claimed it would be," writes Time's Jeffrey Kluger, in reference to the damage the hurricane inflicted on the reputation of President George W. Bush. "But nor was it the Administration's finest hour. The President likes to talk about teachable moments; let's hope this was one of them – and that the White House itself learned a few things too."

The findings, revealed in four draft reports unveiled Wednesday, primarily criticized the administration's early public estimates of the amount of oil spilling into the Gulf, which were 12 times smaller than the final flow rate released in early June.

In a section called "The Boom Wars," the report criticizes a subsequent overreaction by the administration, saying its tripling of resources only muddied the response and pitted parishes and coastal counties against one another. Political considerations also became evident as the White House took firmer control of the disaster, it said, with one edict going out to "keep the parishes happy."

What hurt the early response the most was officials' initial optimism about both the size of the spill and the ability of BP to quickly cap the renegade well, the report concludes. The early estimate of a flow rate of 1,000 barrels of oil per day rose to 5,000 bpd by the end of April, but once BP began its "live feed" of the wellhead on May 20 it became obvious that the flow rate was much higher.

About two weeks after the April 20 blowout at the well, incident commander Thad Allen did cite a "worst case" scenario of 100,000 barrels of oil leaking per day, but couched it in terms of a full wellhead failure, which never materialized.

The administration's agency heads say they weren't hiding anything from the public. In a joint statement, they say the administration was open about a worst-case scenario as early as the beginning of May, less than two weeks after the spill. They also said early spill analyses were partly based on oil already captured instead of the actual flow rate at the wellhead.

"The federal government response was full force and immediate, and the response focused on state and local plans and evolved when needed," said Office of Management and Budget Director Jeffrey Zients and NOAA administrator Jane Lubchenco, in a joint statement. "As directed by the President, the response was based on science, even when that pitted us against BP or state and local officials, and the response pushed BP every step of the way. Finally, and most importantly, the response provided results for the people of the Gulf Coast.”

Nevertheless, the lag in fixing an accurate number to scope of the spill affected not only the government's response, but also the public's trust in the administration's ability to handle a major disaster, according to the commission reports.

"Putting aside the question of whether the public had a right to know the worst-case discharge figures, disclosure of those estimates, and explanation of their role in guiding the government effort, may have improved public confidence in the response," said one of the working papers by the staff of the national oil commission.

Furthermore, "For the first ten days of the spill, it appears that a sense of over-optimism affected responders," the oil commission writes. "While it is not clear that this misplaced optimism affected any individual response effort, it may have affected the scale and speed with which national resources were brought to bear." Even some US Coast Guard responders, the report states, thought the initial approach was "too slow and unfocused."

Eventually, the Obama administration got the situation under control, the report states. "Though the response may have been slow to escalate in the first ten days, by at least mid-May the Coast Guard was fighting a war against the oil."