CLEVELAND – Beginning the fourth year of an unpopular war, President Bush defended his Iraq record on Monday against skeptical questioning. He said he could “understand people being disheartened” but appealed to Americans to look beyond the bloodshed and see signs of progress.

Bush fielded questions for nearly an hour at the City Club, a forum known for its tough interrogations of world leaders. Not only was he grilled about Iraq, but he also was asked to justify his warrantless wiretapping program, U.S. relations with Pakistan and his domestic priorities.

The president was asked why he deemed Iraq – which turned out not to have weapons of mass destruction – as enough of a threat three years ago to launch an invasion, in contrast to nuclear-ambitious Iran today.

“One difference was that, in Iraq, there was a series of unanimous [U.N. Security Council] resolutions that basically held the Iraqi government to account, which Saddam Hussein ignored,” Bush said. Still, he said Iran was a concern, on the question of nuclear weapons and on its role in Iraq.

The White House has accused Iran of meddling in Iraqi politics and of supporting armed militias in Iraq by sending men and weapons, including components for increasingly lethal roadside bombs. Iran and the United States have agreed to talk about Iraq, but Bush said, “It’s very important, however, for the Iranians to understand that the discussion is limited to Iraq. We feel like they need to know our position.”

As the president delivered the latest installment in an upbeat defense of his Iraq policy, opponents used the day after the third anniversary of the invasion to step up their criticism.

Three potential 2008 presidential candidates – Democratic Sen. Joe Biden of Delaware, New Mexico Gov. Bill Richardson and Republican Sen. Chuck Hagel of Nebraska – offered critical assessments at the International Association of Firefighters’ legislative conference in Washington.

Biden said it was time for Defense Secretary Donald H. Rumsfeld to “be told to go home” and for Homeland Security Secretary Michael Chertoff “be given his walking papers.” Richardson said U.S. involvement in Iraq had been “badly mismanaged by the administration.”

Hagel, in an interview at the conference, said many of the predictions and promises made by the administration have fallen short, such as that oil revenues would pay for the war and the conflict would be short.

He also pointed to Vice President Dick Cheney’s assertion last May that the insurgency was in its “last throes.”

“There’s been a credibility erosion for three years,” Hagel said.

On Capitol Hill, some Democrats said there had been progress in Iraq, as Bush asserted, but they said it was clouded by problems across the country. They said Bush had gone to war without enough troops.

“Some positive signs do not mitigate this administration’s gross miscalculations and stunning incompetence in Iraq,” said Rep. Steny Hoyer of Maryland, the No. 2 Democrat in the House.

Senate Democratic leader Harry Reid, D-Nev., said the “policies of the Bush administration and the civilian leadership of our military have made America less safe and left Iraq on the precipice of all-out civil war.”

Bush pointed to success in stabilizing an insurgent stronghold in Tal Afar, a northern Iraqi city of 200,000 near the Syrian border.

“The strategy that worked so well in Tal Afar did not emerge overnight,” Bush said. “It took time to understand and adjust to the brutality of the enemy in Iraq.”

“The example of Tal Afar gives me confidence in our strategy,” the president said.

One woman asked Bush whether he saw terrorism as a sign of the biblical Apocalypse, and a man followed up with how he could restore confidence in U.S. leadership after several reasons for going to war with Iraq later proved false.

“Like you, I mean, I asked that very same question: Where’d we go wrong on intelligence?” Bush said. He said he was working to improve intelligence gathering because “the credibility of our country is essential.”

As for the Apocalypse, Bush said, “I haven’t really thought of it that way. . I guess I’m more of a practical fellow.”

Bush bantered with the audience at times. And despite the probing questions, he received several rounds of enthusiastic applause.

“Anybody work here in this town?” Bush joked to laughter as he responded to question after question.

The White House made no attempt to screen either the audience or the questions, said spokesman Scott McClellan.

However, much of downtown near the hotel where Bush spoke was barricaded off. About 100 anti-war protesters chanted for the Republican president to leave the heavily Democratic city, held signs with peace messages and banged on drums.

Inside, not all the questions challenged Bush’s war rationale.

One member of the audience invited him back for the Cleveland Hungarian Revolution 50th Anniversary next October. Others complimented him on his vision for a nuclear treaty with India and for his “very enlightening” comments about Iraq.

Cheney, attending a political fundraiser in Hanoverton, in northeast Ohio, also defended U.S. involvement in Iraq and said decisions on troop levels would be made without political consideration.

“Our coalition is also helping to build an Iraqi security force that is well trained and well equipped,” Cheney said.