WASHINGTON – President Barack Obama declared Thursday "the buck stops with me" for the nation's security and suggested he would not fire anyone for the Christmas attack on a Detroit-bound airliner... Obama didn't tell intelligence officials to change what they're doing. Instead, he told them to just do it better, and faster. He left it to them to figure out how. ... While Obama promised improved security, his solutions were laced with bureaucratic reshuffling. ... "There is, of course, no foolproof solution," he said. "We have to stay one step ahead of a nimble adversary."