U.S. President George W. Bush said Monday that American soldiers serving in Iraq and Afghanistan were not "fatalists or cynics," and that the government's duty was "to ensure that its outcome justifies the sacrifices made by those who fought and died in it."

"Those who serve are not fatalists or cynics," the president said in a speech at the Arlington National Cemetery marking the Memorial Day.

"From their deaths must come a world where the cruel dreams of tyrants and terrorists are frustrated and foiled -- where our nation is more secure from attack, and where the gift of liberty is secured for millions who have never known it," he said.

Bush said the greatest memorial to the fallen troops could not be found in the words "we say or the places we gather," and "the more lasting tribute is ... a country where citizens have the right to worship as they want, to march for what they believe, and to say what they think."

Even after five years of war, first in Afghanistan and then in Iraq, "our finest citizens continue to answer our enemies with courage and confidence."

"Hundreds of thousands of patriots still raise their hands to serve their country; tens of thousands who have seen war on the battlefield volunteer to re-enlist," he said.

The Iraq war, now in its fifth year, has claimed the lives of over 3,400 U.S. soldiers, and in Afghanistan, more than 320 American troops have been killed since U.S.-led military operations against the country began in late 2001. Many Americans now think that the Iraq war is going badly and favor a withdrawal of troops out of Iraq sometime next year.

Congress passed a war spending bill last month, which would have required the Bush administration to start withdrawing U.S. troops from Iraq by Oct. 1, with a goal of ending U.S. combat operations there by next March, but the bill was vetoed by Bush.

Although Congress dropped the withdrawal timetable in a new wars pending bill last week, because of Bush's renewed veto threat, a CBS News/New York Times poll released a few days ago found that 76 percent of those surveyed said the war in Iraq was going badly, and 63 percent said there should be a timetable to withdraw U.S. troops from Iraq sometime in 2008.