Washington ? President Barack Obama declared Thursday “the buck stops with me” for the nation’s security, taking responsibility for failures that led to the near-disastrous Christmas attack on a Detroit-bound airliner and vowing the problems would be corrected. He said the lapses were widespread but suggested no officials would be fired.

Obama didn’t tell intelligence officials to dramatically change what they’re doing. Instead, he told them to do it better, and faster. He left it to them to figure out how.

Clearly aware of the potential political fallout, Obama struck a tough tone toward the anti-terror fight, taking the rare step — for him — of calling it a “war.”

In one concrete change, the administration is adding more air marshals to flights. Hundreds of law enforcement officers from Homeland Security Department agencies are being trained and deployed to the federal Air Marshal Service, said a government official familiar with the strategy.

There are more than 4,000 federal air marshals, while about 29,000 domestic and international flights take place in the U.S. each day.

In the president’s bleak assessment and a White House-released report about what went wrong, the country got an alarming picture of a post-Sept. 11 debacle: an intelligence community that failed to understand what it had. U.S. intelligence officials had enough information to identify the suspect as an al-Qaida terrorist operative and keep him off a plane but still could not identify and disrupt the plot, and security measures didn’t catch him, either.

Obama announced about a dozen changes designed to fix that, including new terror watch list guidelines, wider and quicker distribution of intelligence reports, stronger analysis of those reports, international partnerships and an interagency effort to develop next-generation airport screening technologies.

More inquiries are on the way.

“It is appalling that we have not learned from our mistakes, eight years after the worst terror attacks in our nation’s history,” said Sen. Olympia Snowe, R-Maine, a member of the Senate Intelligence Committee, which will hold its first hearing on the subject on Jan. 21, probably in private.

While Obama promised improved security, his solutions were laced with bureaucratic reshuffling.

Americans might be surprised that the government was not already taking some of the steps Obama ordered. For instance, he directed the intelligence community to begin assigning direct responsibility for following up leads on high-priority threats.

Obama himself hinted at the difficulties of improving intelligence and security against a terrorist network that devises new methods as fast or faster than the U.S. can come up with defenses.

“There is, of course, no foolproof solution,” he said. “We have to stay one step ahead of a nimble adversary.”