SACRAMENTO, Calif. — A leading contender for the Republican presidential nomination in 2008, Senator McCain of Arizona, said yesterday that the American people are exhibiting a “schizophrenic” reaction to the challenge facing American forces in Iraq.

“Americans are really kind of schizophrenic about this issue,” Mr. Mc-Cain said just prior to a fund-raising lunch for Rep. Dan Lungren, a Republican of California. “They’re frustrated, and they want us to get out, but if we ask the American people if we should set a certain date or a calendar, they agree with the president, and with me, and with Dan, that is a recipe for disaster. We have to have conditions on the ground that indicate we can withdraw.”

Calling the situation in Iraq “very, very tough,” Mr. McCain warned that a precipitous exit by America would have a far-reaching impact. “The consequences of failure are chaos, not just in Iraq, but in the entire region. There’s a great deal at stake here, but I think that we can prevail,” he said.

On the eve of the anniversary of the September 11, 2001, attacks on America, Mr. McCain said he believes the nation is safer today, but not safe enough. “Most experts believed that there would be an additional attack on the United States of America. There hasn’t been,” the senator said. “That can’t be all luck. I think a lot of that has to do with this president’s policies, but particularly the men and women in the Department of Homeland Security and in our intelligence services, who have done a very good job.”

Mr. McCain, who has clashed repeatedly with the White House over issues related to military tribunals, torture, and interrogation techniques, said he expected Congress would pass legislation setting rules for military tribunals before leaving for the campaign trail at the end of this month. A former Navy pilot who spent seven years being tortured and interrogated by the Viet Cong during the Vietnam War, the senator disagrees with aspects of Mr. Bush’s new proposal on tribunals, which calls for the use of secret evidence to convict terrorist suspects.

Asked about the president’s assertion in a speech last week that aggressive “alternative” interrogation methods produced vital intelligence from Al Qaeda captives, Mr. McCain sounded dubious. “I do know that many times when you physically torture someone, they’ll just tell you whatever they think you want to know in order to stop the pain,” the Arizona Republican said. “I know that the Israelis have prohibited torture. … At the same time, there are times and cases where these are literally emergency situations.”

Mr. McCain said reports of ill treatment of prisoners at Abu Ghraib and Guantanamo Bay have hurt America. “This is not just a fight on the ground in Afghanistan and Iraq. This is a war for the hearts and minds of people throughout the world,” he said. “We’re going to have to maintain a careful balance between effective methods and, at the same time, make sure we are not like our enemies.”

Mr. McCain spoke yesterday of “serious mistakes” made by America in Iraq, but he refrained from repeating an assertion that he made last month that, in the lead-up to the war, he warned Mr. Bush and other administration officials against rhetoric that suggested American troops would be received warmly.

Last week, Mr. McCain seemed to retreat a bit from his claims of prescience. “Maybe many of us, and I would plead guilty, have underestimated the difficulty in bringing true democracy to nations that have never known it,” the senator told an international news service, Global Viewpoint, on Thursday.

Mr. McCain said, however, that he remains convinced that America must advance democracy abroad. “Of course, we don’t want to see the House of Saud taken over by Islamic extremists and go the way of Iran with the fall of the Shah. But we also have to understand that, unless there is progress in Saudi Arabia, sooner or later they will fall,” the senator said.

Mr. McCain, who has been seeking to burnish his credentials with conservatives by touring the country in support of candidates such as Mr. Lungren, spoke in sober terms yesterday about Republican prospects in this fall’s congressional election. “I do not underestimate the challenge we face,” he said.

During the press conference, Mr. McCain passed up an opportunity to bash the Democrats, but Mr. Lungren did not. He argued that a Democrat-led Congress would have hampered the war on terror by blocking legislation and undercutting surveillance programs initiated by Mr. Bush. “Not to scare people, but there would be a difference,” the congressman said.

Mr. McCain’s whistle-stop in Sacramento came on the heels of several Democratic presidential hopefuls who have been making treks to California to maintain their political chits. Last week, a Democrat who is struggling in his battle to unseat Governor Schwarzenegger, Phil Angelides, got brief visits from two men considered likely candidates in 2008, a former Virginia governor, Mark Warner, and the Democrats’ vice presidential nominee in 2004, John Edwards.

In July, the putative Democratic frontrunner for 2008, Senator Clinton, made a similar jaunt to the Golden State.