WASHINGTON - George W. Bush was, perhaps appropriately, in a Florida classroom when he learned that America was under attack.
In that instant, Bush was transformed. From education president to counter-terrorist president. From head of a sharply divided government to leader of a country at once horrified and unified - and forever changed - by the bloodiest assault in its history.
Bush, who convened a war council at Camp David, Md., this weekend, found new purpose for his presidency in the debris of Tuesday's disaster: to wage a war against terrorism that would spare future generations from similar attacks.
"This is an administration that is going to dedicate ourselves to winning that war," he said yesterday.
By redefining his presidency in that way, Bush has also, inevitably, raised the stakes for his own political future.
"If he fails here, his administration is finished," said Morton Abramowitz, former head of the Carnegie Endowment for International Peace and now a fellow at the Century Foundation.
"If he captures, destroys, kills bin Laden, then I think most people will consider that a success," Abramowitz said, referring to Osama bin Laden, whom the president now calls "a prime suspect" in last week's plot.
Administration officials emphasized, and outside analysts agreed, that the counterterror campaign would last years, not weeks or months.
"We may be on the cusp of something very much like the Cold War at this time," said Thomas Henriksen, a specialist on international affairs at Stanford University's Hoover Institution. "It's going to be a very lengthy struggle to eradicate terrorism."
Less than eight months ago, Bush came to power on an agenda of education reform and tax cuts. Recently, he turned to the problem of a worsening economy. He still must tackle domestic issues, including a recession that economists say is inevitable as the aftershocks from Sept. 11 ripple through the economy.
But "the nation must understand," Bush said, tat "this is now the focus of my administration. ... Now that war has been declared on us, we will lead the world to victory."
No recent president has confronted such a formidable test, much less a president in his first year in office, one with no extensive background in military or foreign policy. Some Americans still question the legitimacy of Bush's election. Many more have had lingering doubts about his capacity to do the job.
Yet another media recount of the disputed Florida election, the most extensive to date, had been scheduled to be made public this week. And just minutes before the first hijacked jetliner exploded into the World Trade Center, Democratic pollsters released a new opinion survey showing that more than two in five voters believed Bush was "in over his head" as president.
With the attack, those attitudes, and the entire political landscape, have been reordered.
Opinion surveys show an overwhelming outpouring of support for Bush. The American people have a high degree of confidence in his and the government's ability to root out and punish those responsible, according to surveys.
Bush's central political challenge will be to maintain that popular support in the face of a counter-terror struggle that may be more difficult and prolonged than much of the public recognizes.
"You will be asked for your strength," he said in a radio address to the nation yesterday, "because the course to victory may be long."
As Bush moved to assert his leadership and reassure a fearful public, his friends and supporters said they weren't surprised that he was getting generally positive marks for his handling of the situation.
"I always believed that the president would shine the brightest during crisis. When times are worst, he's at his best," said Mark McKinnon, who was a key campaign adviser.
His most striking appearance may have come Thursday. During an Oval Office session with reporters, Bush pledged, in unusually forceful terms, that America would conduct a successful world war on terrorism. Then, in practically the next breath, he grew tearful when asked about his personal feelings.
McKinnon called it "a seminal moment, when America and the world saw the best qualities of the president - both compassion and leadership."
Some critics, however, who include both liberals and conservatives, remain unconvinced. They said they found troubling signs in Bush's performance, which began unevenly but steadied as the week progressed.
Concerns were expressed, mostly in private, over Bush's delay in returning to Washington after the attack and about the tepid quality of some of his rhetoric, which seemed to raise questions about the strength of his leadership.
Among those coming to Bush's defense was his father. The former president said he was "annoyed" that his son had been criticized "for following security procedures, not rushing right back to Washington" on Tuesday.