President Bush defended new limits on legal rights imposed by his administration in the war on terror, declaring that "the Constitution is sacred" and will not be undermined in the effort to improve Americans' security.

In an interview with a 60 Minutes II special broadcast airing Wednesday night on the anniversary of the terrorist attacks, Bush said he is pleased with the job being done by the Justice Department, despite criticism from civil liberties groups that Americans' individual freedoms are being eroded.

Among the Bush administration moves that have come under criticism are new authority in terror cases to imprison Americans indefinitely, allowing federal agents to monitor attorney-client conversations in federal prisons, the detention of thousands of Middle Eastern men who entered the United States since 2000 and immigration hearings that are no longer public.

Bush told the CBS News program that questioning and court review of those actions is healthy -- "part of America."

"We will protect America," he said. "But we will do so within the guidelines of the Constitution, confines of the Constitution. ... But the American people got to understand that the Constitution is sacred as far as I am concerned. "

The president reiterated that the U.S. policy of "regime change" in Iraq has not changed. Bush has made toppling Iraqi President Saddam Hussein a priority because of his pursuit of weapons of mass destruction, though he has not said how he plans to realize the goal and has received little support from other world leaders.

"I get all kinds of advice," Bush said. "I'm listening to the advice. I appreciate the consultations."

Bush recalled his thoughts as the terrorist attacks of last Sept. 11 and the days after unfolded.

"I can remember sitting right here in this office thinking about the consequences of what had taken place and realizing it was the defining moment in the history of the United States," Bush said of his time on Air Force One as it tore across the country in the hours after planes crashed in New York, Washington and Pennsylvania. "I didn't need any legal briefs, I didn't need any consultations. I knew we were at war."

Days later, at Ground Zero in New York meeting with the families was one of the most painful moments.

"I felt the same now as I did then, which is sad," Bush said. "And I still feel sad for those who grieve for their families but through my tears I see opportunity."

In an opinion piece for Wednesday's editions of The New York Times, Bush said the attacks have "brought new clarity to America's role in the world," along with opportunities.

"America's greatest opportunity is to create a balance of world power that favors human freedom," he wrote.

While he didn't mention Iraq specifically, Bush said the United States will defend peace by preventing violence by terrorists and "outlaw regimes."

"We will use our position of unparalleled strength and influence to build an atmosphere of international order and openness in which progress and liberty can flourish in many nations," he wrote. "We preserve this peace by building good relations among the world's great powers and we extend this peace by encouraging free and open societies on every continent."

Repeating his reasoning for a possible pre-emptive attack on Iraq, Bush said the United States must also confront regimes that support terror and seek nuclear, chemical and biological weapons.

"On this issue, the consequences of inaction could be catastrophic," he said.