President Bush on Monday reminded the world that while the path toward Iraqi democracy has been rocky, so was the path to American democracy more than 200 years ago.

In a speech in Philadelphia, birthplace of the U.S. Constitution and "the city where America's democracy was born," the president argued that, like the Americans who gathered in Philadelphia for the constitutional convention in 1787, Iraqis are showing their resolve to govern themselves despite some setbacks.

Iraqis have already begun to go to the polls to elect a 275-member national assembly. Thousands of candidates from more than 300 political groups are participating in the vote and turnout is expected to be higher than it was in October when Iraqis approved a new constitution.

"It'll be a remarkable event in the Arab world," Bush said of Thursday's elections, adding that cities like Najaf, Baghdad and Mosul are full of political posters. Candidate ads fill television and radio airwaves and Sunni leaders who urged boycotts of previous elections are now encouraging their followers to vote.

"Despite terrorist violence, the country's buzzing with the signs and sounds of democracy in action ... Our troops see this young democracy up close," Bush said.

Bush repeated his oft-stated goal that terrorists must be defeated in Iraq for democracy to succeed. That fight, he said, is part of the global War on Terror, a war that began when 19 terrorists attacked America on Sept. 11, 2001.

"Like generations before us, we have accepted new responsibilities, confronting dangers with new resolve," Bush told the audience at the World Affairs Council. "We're taking the fight to those who attacked us and to those who share their murderous vision for future attacks. We will fight this war without wavering and we will prevail."

An American Role Model

Saying the fledgling U.S. democracy was plagued with "disorder and upheaval" in its earliest days, Bush described a series of struggles going on with various groups within the United States that stalled democratic progress.

"Our founders faced many difficult challenges, they learned from their mistakes … and they adjusted their approach," Bush said.

Bush noted that the Articles of Confederation failed the first time they were presented, that it took years of debate and compromise before the U.S. Constitution was approved, and that it took years of civil war to spread freedom to all people.

"It is important to keep this history in mind as we look at the progress of freedom and democracy in Iraq," Bush said. "No nation in history has made the transition to a free society" without some "setbacks" and "false starts."

Once Iraq has the first and only constitutional democracy in the Middle East, Bush said it will help reduce the threat of terrorism in that region and hopefully help democracy spread.

"By helping democracy succeed in Iraq, we bring greater security to our citizens here at home," he said. "The terrorists know that democracy is their enemy and they will continue to fight freedom's progress with all the hateful determination they can muster."

The president was in Pennsylvania Monday as part of his ongoing fight to rebuild slumping support for the war. In his first two speeches, Bush claimed new strength for Iraq's troops and economy while acknowledging difficulties caused by continuing violence. His speech Monday was meant to express his determination to help Iraqis build institutions for a lasting democracy.

Pennsylvania also is the home state of a leading Iraq war critic, Democratic Rep. John Murtha, who planned to speak at 1:30 p.m. ET and repeat his call to bring the troops home from a fight he says has become too violent and out of control.

Murtha, a traditionally hawkish former Marine, has galvanized war critics and been an outspoken counterpoint to Bush's portrayal of success in Iraq. Since Murtha first called for troop withdrawal last month, the president has talked more openly about difficulties in Iraq and has laid out more detailed benchmarks for progress there.

Bush: Iraq in a 'Remarkable Transition'

Iraqis are preparing to vote under tight security to elect a parliament that will run the country for the next four years. The election will be the first under the new constitution ratified in an Oct. 15 referendum and will complete the steps toward democratization following the ouster of Saddam Hussein's government.

Bush also discussed how Iraqis have completed each of the political hurdles set out before them until now and will continue to do so with Thursday's election.

Although it's a time of struggle, it's also a time of "great hope and achievement for the Iraqi people," Bush said.

It's a "remarkable transition for a country that has virtually no experience with democracy," he said. "There's still a lot of difficult work to be done in Iraq but thanks to the courage of Iraqi people, the year 2005 will be recorded as a turning point in the history of Iraq, the history of the Middle East and the history of freedom."

The U.S. helped negotiate a new plan for a transitional Iraqi government in November 2003. Since then, Iraqis have adopted a constitution that guarantees personal freedoms, something "unprecedented by the Arab world," Bush said. The have also met milestones set for drafting that constitution and for holding previous elections.

In January 2005, almost 8.5 million Iraqis "defied the car bombers and assassins to cast their ballots," Bush said. Even though they were marred by reports that Sunni Arabs refused to fully participate in the process, "the January elections were a watershed event for Iraq and the Middle East," Bush said.

Bush said Iraq's constitution "marks the dawn of a new age in Arab life ... through hard work and compromise, Iraqis adopted the most progressive, democratic constitution in the Arab world."

Voter turnout will be an important benchmark for success in Iraq, particularly among the disaffected minority Sunni Arabs who have been the foundation of the insurgency. Zalmay Khalilzad, the U.S. ambassador to Iraq, predicted Sunday that Sunnis would turn out in large numbers, win 40 to 55 seats in the assembly and become more involved in government.

Many Sunnis boycotted the Jan. 30 election to protest the continued U.S. military presence. That enabled the Shiites and Kurds to dominate parliament, a move that sharpened communal tensions and fueled the insurgency.

Bush said many Sunni Arabs who lived a more privileged life than their fellow citizens under Saddam Hussein are realizing they need to be part of the government in order to not be marginalized. The more Iraqis involved in the process, Bush said, the fewer the "adversaries" — also called "rejectionists, Saddamists and terrorists" by the president — who will try to derail the elections with violence.

This time, more Sunni Arab candidates are in the race. Changes in election law have enabled parliamentary seats to be allocated mostly by province rather than by a party's nationwide total. That change, accompanied by voting, all but guarantees a sizable Sunni bloc in the next assembly.

Turnout in January was about 58 percent but less than 5 percent in the predominantly Sunni province of Anbar, a hotbed of insurgency. In October, it was reported that as many as 93 percent of Sunnis in Fallujah went to the polls as did 75 percent of Sunnis in Salahuddin.

"More Sunnis are involved because they see Iraqi democracy succeeding ... they must participate to have a voice in their nation's affairs," the president said, quoting one Sunni leader as saying: "This election is a vote for Iraq. We want a national Iraq, not a sectarian one."

The United Nations and other groups and governments are playing a part in making sure Iraq's democracy gets of its feet, Bush said, despite how some in those corners opposed the invasion of Iraq in the first place.

"Whatever differences there were over the decision to liberate Iraq, all free nations share a common interest — building an Iraq that will fight terror," Bush said. "Iraqis are determined to overcome [terrorists] and build a free nation and they require our support."

In a question-and-answer session after his speech, Bush again defended the decision to use military force to oust Saddam. He noted that many governments around the world believed the deposed Iraqi dictator possessed weapons of mass destruction — the main reason the administration used for invading Iraq.

While the administration has taken heat for ever alluding to the idea there may have been a link between the Sept. 11, 2001, attacks and Iraq, Bush said that the attacks on American soil more than four years ago was a wake-up call to him that threats to the United States overseas cannot be ignored. Saddam was one of those threats, he added.

"I made a tough decision," Bush said. "And knowing what I know today I'd make the decision again. Removing Saddam Hussein makes this world a better place and America a safer country."

Bush also estimated that 30,000 Iraqi civilians "have died as a result of the initial incursion and the ongoing violence against Iraqis.

"We've lost about 2,140 of our own troops in Iraq," he added.

Monday's Iraq speech is Bush's third, part of a campaign to win support for the mission that most Americans say in polls has not been carried out properly by the administration. The final address in the series is planned for Wednesday in Washington.

In these speeches, Bush also has been battling Democratic calls for what he calls "artificial timetables" for troop withdrawal. The president said he will take his advice from military commanders on the ground and their recommendations for how many troops to keep in Iraq — and that advice will be based on the security situation in Iraq, first and foremost.

The White House says substantial U.S. troop withdrawals are likely next year but that setting any timetable sends the wrong signal to the insurgents and the troops.

Leon Panetta, former President Clinton's chief of staff, said regardless of one's political party, "the president certainly set out the hopes I think we all share," and those include holding successful elections, establishing a democracy and ensuring that Iraqis can secure their own country.

"I think the real test is going to be whether or not we can achieve these goals ... how do we ensure Iraqis establish sufficient security for that country, sufficient security for their forces," Panetta said, adding that Bush's recent speeches on the issue have helped frame the argument for why U.S. troops cannot all be pulled out right away. "But I think it's important to have the debate that we're having. I think the president needs to engage in that debate and he has with his speeches."

An Associated Press-Ipsos poll taken this month indicates Bush's public relations campaign might be working. He improved his job approval rating from 37 percent in November to 42 percent. While still relatively low, that's his highest figure since summer.

The U.S. government's Arabic-language television service, Alhurra, carried Bush's remarks live, but it was not shown on Al-Jazeera or Al-Arabiya or any of the Iraqi television stations.

The Associated Press contributed to this report.