John F. Kerry and John Edwards made their public debut as the 2004 Democratic presidential ticket Wednesday and left little doubt they will spend the next four months hammering President Bush on the economy and touting values and optimism to improve their party's image among skeptical voters in rural communities and down South.

While the presidential campaign has been consumed with the war in Iraq and threats of future terrorist attacks for months, the two senators talked mostly about economic distress and disparity during joint appearances from the Allegheny Mountains of Pennsylvania to the banks of Lake Erie here in Ohio, and culminating in a late-night rally in St. Petersburg, Fla. These populous states are three of the biggest battleground prizes for this fall.

The Democratic nominee and his running mate, accompanied by their wives and children on the hustings for a four-day swing, vowed to shrink the gulf between the wealthy and the middle class by making college and health care more affordable and jobs better-paying and more abundant. They would accomplish all this in part by repealing the tax cuts benefiting Americans making more than $200,000 annually and by spending the revenue on domestic programs.

But Bush, who considers national security the dominant campaign issue, traveled to Edwards's home state of North Carolina to give voters a stern warning. The freshman senator is not qualified for the presidency, he said. The unexpected broadside by Bush prompted Kerry to change an early-afternoon speech in Dayton, Ohio, to defend his vice presidential pick and take a personal swipe at Bush.

Edwards has "more experience than George Bush and better judgment than he when he became president," Kerry said. Bush "was right that Dick Cheney was ready to take over on day one, and he did and has been ever since, folks, and that's what we have got to change."

Republicans consider Edwards's lack of national security expertise among his biggest liabilities. They said they plan to raise the issue relentlessly, especially by contrasting him with Cheney, a former defense secretary and a chief architect of Bush's foreign policy. This is part of a broader GOP plan to portray Democrats as soft on defense and terrorism.

Kerry, who expressed his doubts about Edwards's readiness to be president a few months ago, described his running mate throughout the day as highly qualified for the White House, but he focused on Edwards's domestic expertise and humble origins. "This is a man who defines opportunity because he grew up watching his father go to work at the mill and his mother go to work in a furniture store, and he became the first man in his family to graduate from college," Kerry said here.

Portraying themselves as a "new team for a new America," the two Democrats used the words "optimism" and "values" several dozen times to frame their campaign as an upbeat movement to change the country.

Edwards is "a man who shares my unyielding optimism, that sense of hope about our nation, about the possibilities of the future," Kerry said to loud cheers at their first public rally. "Together, we are going to restore to America the values that belong to Americans."

Edwards echoed Kerry in the opening moments of his first speech. "With John Kerry as president, we are going to restore real American values," he said.

Edwards was greeted with a torrent of rain, but it did not stop him from showing why Kerry picked him and why many Democrats consider him presidential timber for the future. Edwards lit up the huge crowd here with his call for economic fairness and with a spirited defense of the Massachusetts senator's national security heft.

"We Americans need a president who will lead the world, not bully it," Edwards said. "We need a commander in chief that will protect and keep the American people safe, who will keep our military strong and stand for the men and women who serve this country. For John Kerry, this is personal."

The two Democrats played to each other's strengths throughout the day, with Edwards often talking up Kerry's foreign policy expertise and Kerry harkening to Edwards's humble origins and ability to speak with clarity and conviction about the everyday problems facing Americans. Kerry called Edwards "a different kind of electricity."

Kerry aides said this is a preview of the roles each will play in the months ahead. While they talked about various issues on Wednesday -- from Bush's foreign policy to values to the economy -- the campaign signaled that Edwards will try to carry the ticket's economic message into areas where job losses make that appealing, while Kerry will be the one to carry the national security message, with Edwards cheerleading Kerry as commander in chief.

Kerry adviser Tad Devine said Edwards will open doors for Kerry because the North Carolina senator, 51, was once a poor kid from a small town before becoming a rich man in the nation's capital. "He can go places where Democrats typically have not spent a lot of time, for example small rural communities," Devine said. "It gives us the option to talk to voters who the party has sometimes taken for granted."

The Edwards pick instantly changed the campaign's political calculation, as Kerry unveiled a television ad in North Carolina, a state Democrats had not planned to contest without the home-state senator on the ticket. Bush has declared that he will carry the South; polls show the president leading in every southern state except Florida.

"There has been a trend over the years that has rejected those liberals that come home and talk conservative," House Majority Leader Tom DeLay (R-Tex.) said. "That's why Republicans are the overwhelming majority party all across the South."

With an eye on the South, Kerry and Edwards talked often about religious faith, which plays a more prominent role in the politics of the region. They also had some lighthearted fun that underscored the youthfulness infused into the ticket by the addition of Edwards.

"We think this is a dream ticket. We have got better vision. We have got better ideas. We've got real plans. We've got a better sense of what is happening to America. And we've got better hair," Kerry, 60, said. The nominee seemed unusually focused on hair Wednesday. At a photo op at his wife's 88-acre estate, Kerry said: "It's a thrill for me to have another guy with hair on the road."

Later Kerry quoted his wife, Teresa Heinz Kerry, telling him: "You just lost the bald vote."

Sens. John F. Kerry (D-Mass.) and John Edwards (D-N.C.) appear as running mates for the first time at a rally in Cleveland. Sens. John Edwards and John F. Kerry walk in Pittsburgh with their wives, Elizabeth Edwards, left, and Teresa Heinz Kerry.