In an appearance before minority journalists, the Massachusetts senator said he would have jumped into action more quickly than President Bush did on Sept. 11, 2001, when he learned of the terrorist attacks.
The president spent seven minutes reading to Florida elementary school children after learning that hijacked planes had been flown into the World Trade Center in New York.
"Had I been reading to children and had my top aide whisper in my ear that America is under attack, I would have told those kids very nicely and politely that the president of the United States has something that he needs to attend to," Kerry said.
Kerry also ridiculed Mr. Bush's claim that the nation has "turned a corner" in an era marked by terrorism and economic recession.
"Just saying that you've turned a corner doesn't make it so. Just like saying there are weapons of mass destruction (in Iraq) doesn't make it so. Just like saying you can fight a war on the cheap doesn't make it so. Just like saying 'mission accomplished' doesn't make it so," Kerry said.
"The last president who used that slogan, who told us that prosperity was just around the corner, was Herbert Hoover during the Great Depression," he said.
Steve Schmidt, a spokesman for the Bush-Cheney campaign, countered that Kerry is running a "pessimistic campaign" and criticized the Democrat for his vote against the $87 billion aid package for Iraq and Afghanistan. Schmidt said that vote "raises serious issues of credibility and his ability to lead our nation in the war on terror."
Meantime, President Bush was campaigning Thursday in the swing state of Ohio, a state that has lost tens of thousands of jobs since he took office. The president acknowledged the economic woes and highlighted his determination to work for an improved economy in a second term.
"We've been through a lot. Ohio's been through a lot," he said.
Before Mr. Bush spoke, the White House issued a two-page memorandum on proposed labor law changes so that workers can choose time off instead of overtime pay, a notion that has met stiff resistance in the Republican-controlled Congress.
The AFL-CIO and other opponents say the proposals will hurt workers financially while savings companies billions on overtime pay.
Mr. Bush only mentioned the proposals once, in response to a question from the audience at the end of his appearance. The president said the government should allow employers to say to employees that they can spend more time with their families.
"Government should be standing side by side with people," the president said to applause.
In his appearance before a group of minority journalists, Kerry drew applause when he referred derisively to Mr. Bush's recent decision not to speak before the NAACP. He said that as president, he would meet with the members of the Congressional Black Caucus, civil rights groups and other minority organizations as part of an effort to build a more united nation.
"America is still a house divided, in health status, living standards, access to capital, schools, all the things that make a difference," he said.
Kerry cited statistics that 50 percent of black men in New York City are without work, while in some cities 40 percent of Hispanic children are school dropouts.
"How can we accept the fact that one of every five Asian-Americans attempting to buy or rent a home faces discrimination?" he asked.
Kerry also pledged to "open the doors of the White House to Native Americans." And in an unusual pledge, he said he would prod the nation's news executives to increase the number of jobs for Native Americans in the media.
Having traveled 1,700 miles by bus since leaving the convention, Kerry starts the second week of his cross-country campaign journey at the historic train station in St. Louis, reports CBS News Correspondent Bob Fuss.
Several thousand supporters, who had to stand in line for hours to get through the metal detectors, were gathered in front of the train that will take Kerry west through Missouri, Colorado, New Mexico and Arizona.
One of the cars on the train is a 1914 Pullman used by Harry Truman, who made whistle-stop train tours a standard of modern campaigning.