Keeping America safe, fighting the war on terrorism and military operations in Iraq are major issues in this year's presidential campaign - the first to be held since the September 11 attacks three-years ago. Saturday is the third anniversary of the day hijackers crashed passenger planes into the World Trade Center in New York, the Pentagon outside Washington and a field in Pennsylvania, killing nearly 3,000 people.

The attacks changed the nation in many ways and altered the priorities of voters who in previous elections put economic concerns before all other issues.

With less than two months before the November election, President Bush and challenger John Kerry mention the war on terrorism and the continuing conflict in Iraq in nearly every speech on the campaign trail.

The September 11 attack was the defining moment of the Bush presidency, and Mr. Bush says protecting the United States from the continuing danger of terrorism is something he thinks about everyday. "Three days after September the 11, I stood where Americans died, in the ruins of the Twin Towers. Workers in hard hats were shouting to me, "Whatever it takes." A fellow grabbed me by the arm and he said, "Do not let me down." Since that day, I wake up every morning thinking about how to better protect our country. I will never relent in defending America, whatever it takes," he says.

Voters in a recent USA Today - Gallup Poll named the war on terrorism and the economy as the two most important issues facing the country this presidential election year.

They listed Iraq as their third-biggest concern.

President Bush says the lessons learned from the September 11 attacks helped him decide to go to war against Saddam Hussein's regime in Baghdad.

Democratic presidential nominee John Kerry has focused much of his criticism of the Bush administration on the continuing violence in Iraq. "When it comes to Iraq, it is not that I would have done one thing differently from the President, I would have done almost everything differently. And, if there's one thing I learned from my own service, I would never have gone to war without a plan to win the peace," he says.

Stuart Rothenberg writes about politics for Roll Call magazine and is a VOA analyst for this year's election.

Mr. Rothenberg says many Americans will decide whom to vote for based on how they evaluate the candidates' positions on fighting terror and the war in Iraq. "I think if the voters evaluate George Bush generally on terrorism I think that is an asset for him. If the voters look specifically about Iraq and casualties and car bombs and things like that, that is not nearly as good for the president," he says.

American University professor and presidential historian Alan Lichtman says this is the first time since the Vietnam War in the 1960's that foreign policy related issues are among the most serious concerns of the voters.

Despite massive increases in security at airports and borders, the creation of the Department of Homeland Security, tougher immigration policies and legislation giving broad powers to law enforcement, he says there is still a sense of vulnerability among many Americans.

That may be one reason Congress is moving quickly to adopt recommendations from a commission that investigated the September 11 attacks, holding more than a dozen recent hearings during what is normally a summer recess.

Mr. Lichtman says even after three years the terrorist attacks on New York and Washington are having an extraordinary impact on this year's race for the White House. "The September 11 attacks, I think, define this campaign. So much of what this president has been doing has been in response to September 11, including in his view the war in Iraq, homeland security and the Patriot Act. A whole series of issues coming out of 9-11 will be central to this election," he says.

U.S. officials have repeatedly warned that intelligence information indicates another terrorist attack may occur in the United States before the November 2 election.

Analysts say concerns about future attacks are likely to play a major role in how Americans vote on Election Day.