With that formulation, the president sought to focus on the moral component of the wars in Iraq and Afghanistan, which he said have "made the world a better place."

Bush said that "by bringing hope to the oppressed," U.S. troops overseas "are making America more secure." He credited American leadership and resolve with changing the world for the better, and vowed that U.S. forces would "never be intimidated by thugs and killers."

While the president didn't offer much in the way of new ideas or phrases -- there was nothing comparable to the "axis of evil" or the right of pre-emptive strikes -- he threw down the gauntlet to any political opponents who plan to take him on over the war in Iraq.

"I thought he was measured, he was confident of where we've been, where we're going," said Danielle Pletka, who heads the defense and foreign section of the American Enterprise Institute.

"The Democrats have really tried to shake his confidence in having waged war on Iraq. He was defiant, and I think rightly so. The things he's really getting hit on, he didn't shy away from. He didn't avoid them. He came right back and he said, no, these are things I think will make us safer, will make our world a better place."

At the same time, Bush focused on the rosy side of the picture in Iraq, talking about the hoped-for march toward Iraqi sovereignty by the end of June and the increasing role he said Iraqis are playing in providing for their own security.

"The president totally dodged the question of his failure to find any weapons of mass destruction in Iraq," said Joe Cirincioni, director of the nonproliferation project at the Carnegie Endowment for International Peace. "The major problem the president faces is that everything he said last year about Iraq's weapons of mass destruction simply wasn't true."

Jim Walsh, direction of Harvard University's program on nuclear security, said the president's speech was well-written and well-delivered but was lacking in substance.

"There's a lot of good lines, but there's not much 'there' there on any of the security-related issues," Walsh said.

He added that the lines between Iraq and the war against al-Qaida were consistently blurred throughout the speech, as if to strengthen the link in the public's mind.

"He goes from terrorism to homeland security and the Patriot Act to Afghanistan to Iraq to Libya, back to terrorism, back to Iraq and then on to the Middle East - trying to weave them together as if they're all the same thing," Walsh said.

While the administration has backed off claims that there was evidence linking Iraqi leader Saddam Hussein to al-Qaida or the Sept. 11 attacks, Bush sought to achieve the same effect through a rhetorical device, Walsh said.

That approach may prove effective as the presidential campaign nears, said Tim Lomperis, chairman of St. Louis University's political science department and a former military intelligence officer.

"I think that Bush has really created a kind of momentum in his favor," Lomperis said. "The Democrats are going to have a hard time taking Bush to task on the war after tonight, though events could change that. The Republicans were standing up and applauding every half-sentence. They were going for blood. I've never seen so many people in uniform in the audience as this. This was kind of a war cheerleading speech. Bush was kind of folding Iraq into the larger war on terrorism, which is going to make it much harder for the Democrats to disentangle it."

In many ways, Tuesday's speech marked a logical progression from Bush's first two State of the Union speeches, in terms of how he addressed the war on terrorism.

Two years ago, Bush condemned outlaw nations that have weapons of mass destruction and ties with terrorists. On the heels of victory in Afghanistan, Bush said the war on terrorism was in its infancy, and he warned that America would not stand idly by as threats to it increased. Invoking the phrase "axis of evil," he singled out Iraq, Iran and North Korea for special concern.

Last year, Bush castigated Saddam as a brutal dictator and made it clear that unless he disarmed Iraq within a few weeks, U.S. military forces would do so.

Tuesday, with the two wars behind him, Bush focused more on the aftermath of combat - the effort to rebuild Iraq and establish a democratic society and the possibility of changing the equation in the Middle East as a result.

Clifford May, president of the Foundation for the Defense of Democracies, a think tank founded after the attacks of Sept. 11, 2001, said he was impressed by the way Bush handled that issue in his speech.

The president said the United States "has not come all this way - through tragedy and trial and war - only to falter and leave our work unfinished."

"I think that's important," May said. "While we're the best the world has ever known in terms of conventional warfare, and we're learning how to win a low-intensity war against insurgents and terrorists, the biggest challenge facing America is to help bring democracy and freedom to parts of the world where they've known only oppression.

"We have so much more to do in this regard, and I think there needs to be so much more focus on this challenge. The president's talking about all the work that's not yet done - and the American effort to bring freedom and democracy needs a whole lot more work."

In some ways, this was a more challenging speech for Bush. Rather than laying down the law to other nations as he did in 2002, or giving Iraq a last chance as he did last year, he now faces the more complex task of nation building - something that as a candidate in 2000 he had rejected out of hand.

In addition, rather than speaking to a shocked nation in 2002 or a largely unified nation last year, he now faces a public with sharp questions about the justification he gave last year for the war - the presence of large quantities of weapons of mass destruction in Iraq. Nearly nine months after the end of major combat, no such weapons have been found.

While saying little about the weapons, Bush noted that he had ended the torture chambers and killing fields of Saddam.

He also scoffed at critics who call for the "internationalization" of the conflict in Iraq, noting the dozens of nations that are helping.

Jon Alterman, director of the Middle East program at the Center for Strategic and International Studies, said that Bush was largely defensive in his speech but that his tone "soared" when he spoke of his goal of a more moderate and democratic Middle East as a result of U.S. actions.

While Bush's speech lacked specifics, that's not a problem, said Rep. Todd Akin, R-Mo., a member of the House Armed Services Committee. Bush was focusing on the big picture - how the United States "can export the ideas that make America free and prosperous."

Bush does well both in setting objectives and managing the government to meet them, and in communicating a vision that inspires others, Akin said. "His leadership style is confident, visionary and hopeful," Akin said.

But Rep. Ike Skelton, D-Mo., a senior member of the House Armed Services Committee, said that Bush "failed to distinguish between the war on terrorism caused by al-Qaida fanatics on one hand and the guerrilla warfare that our troops are facing in Iraq on the other."