"No matter how frustrating the fight in Iraq can be, no matter how much we wish this war was over, the security of our country depends directly on the outcome of Iraq," Bush told an audience at East Grand Rapids High School, vowing to keep troops in Iraq until the job is done.
Reid, D-Nev., fired back at Bush, saying "no one wants us to succeed in Iraq more than Democrats."
"We heard the same old story from the president today because his strategy calls for more of the same. It’s a failed strategy for our troops in Iraq, it’s a failed strategy for our security at home and it’s dangerous that the president refuses to recognize the reality on the ground in Iraq," Reid said from the Senate floor.
• SPEAKOUT: Do you think the war is lost?
Reid ignited a political firestorm after saying Thursday that the war in Iraq is lost and Bush's plan to send more troops there to quell sectarian violence won't work.
"I believe myself that the secretary of state, secretary of defense and — you have to make your own decisions as to what the president knows — (know) this war is lost and the surge is not accomplishing anything as indicated by the extreme violence in Iraq (Wednesday)," Reid said.
Bush traveled to Grand Rapids, Mich., Friday to defend his leadership in the war and to continue pushing Congress to send him a war-funding bill without a timetable to begin withdrawing U.S. troops from Iraq.
"Despite the initial signs of progress on the ground, despite the fact that many reinforcements have not even arrived, the Democratic leadership in Congress is pushing legislation that would undercut the strategy General David Petraeus has just started to pursue," Bush said.
"If we were to concede Iraq to basically Al Qaeda, in a sense, they would follow us here."
Republicans blasted Reid's comments on the House floor Thursday night.
"What a terrible message for our troops fighting this very minute," said Rep. Kay Granger, R-Texas. "Instead of a roadmap to success, we are being asked to support a plan for defeat. We're being asked to announce to our enemies a date for surrender."
The partisan bickering comes as Bush promises to veto legislation funding the wars in Iraq and Afghanistan that includes any timetable to begin withdrawing U.S. troops.
Bush sent Congress a request to fund the wars in Iraq and Afghanistan 74 days ago, saying "our men and women should not be caught in the middle of these debates."
House and Senate negotiators still need to agree on a final version of the war spending bill before it can be sent to the president. The Senate version sets an exit date to begin within 120 days of the bill's passage, with a completion goal of March 31, 2008. The House bill would order all combat troops out by Sept. 1, 2008.
Lawmakers responded to Reid's comments, saying the nation cannot give up the fight in Iraq or it will face terrorists on American soil.
"Majority Leader Reid's willingness to withdraw and declare defeat — in the face of horrific acts of terrorism — would be a mistake for the ages," said Sen. Lindsey Graham, R-S.C., in a statement.
Republican White House hopeful Rep. Tom Tancredo, R-Colo., said Reid should be held responsible for the deaths of all American soldiers in Iraq, calling his comments "reckless" and "brash."
Some Democrats backed up Reid.
"Our soldiers didn't lose the war," said Rep. Dennis Kucinich, D-Ohio. "I maintain the war was lost the minute the White House fabricated a cause for war."
Democratic Rep. Jack Murtha said the war cannot be won by military force.
"I am proud of these troops and what they have done," said Murtha, D-Pa. "They won the war and the mission was accomplished. We cannot win it militarily. It can only be won diplomatically."
Bush met with Reid and House Speaker Nancy Pelosi Wednesday at the White House about the Iraq war funding bill and the stalemate over the legislation. Reid said he told Bush he thought the war could only be won by political, economic and diplomatic means.
Rep. Pete Hoekstra, R-Mich., said Reid's comments tell Al Qaeda and the rest of the world that terrorists have won.
"They are outlaws. They are criminals. And we cannot concede this to them like the majority leader in the other body did today," Hoekstra said.
America must stand firm in its mission to fight terrorists, said Rep. Ileana Ros-Lehtinen, R-Fla.
"Whether or not some choose to acknowledge it, we are at war with militant Islamists who seek our destruction," Ros-Lehtinen said. "Yet some on the other side of the aisle today announced that the war is lost in Iraq. This comment shows little understanding of the ability and determination of our men and women in the Armed Forces."
FOX News' Wendell Goler and The Associated Press contributed to this report.