Democratic presidential candidate John F. Kerry today chided President Bush for spurning an invitation to address the NAACP and urged African Americans to help defeat a man he accused of dividing the nation by race and wealth.

Addressing the annual convention of the NAACP in Philadelphia, Kerry, 60, a four-term senator from Massachusetts, said the presidential contest on Nov. 2 will be "the most important election of our lifetime," and he urged the black community to mobilize to register more voters and get them to the polls.

"Our job between now and November is to end the division between the fortunate America and the forgotten America," Kerry told the nation's largest civil rights organization. "We need to come together in the 21st Century as one America, and I intend to lead us to do that."

Referring to Bush's decision not to address the NAACP, Kerry told the crowd, "As a campaigner, I know a little something about scheduling conflicts and hostile environments. But when you're president of the United States, you can pretty much say where you want to be. And when you're president, you need to talk to all the people, and that's exactly what I intend to do. I will be a president who truly is a uniter, not one who seeks to divide our nation by race or riches or by any other label."

Kerry added, "You know, the president may be too busy to speak to you now, but I've got news for you, he's going to have plenty of time after November 2nd."

The White House initially cited a scheduling conflict in turning down the NAACP's invitation, but Bush later made it clear that he resents harsh criticism that he said has been directed at him by NAACP leaders. He recently described his relationship with those leaders as "nonexistent" and told reporters, "You've heard the rhetoric and the names they've called me."

Instead of the NAACP, Bush plans to address another civil rights group, the Urban League, at its convention in Detroit next week.

In an effort to defend his decision and reach out to African American voters, Bush administration officials today took potshots at NAACP leaders, and the campaign of Bush and Vice President Cheney began airing ads on black radio stations in Philadelphia, Detroit and other cities.

Secretary of Education Rod Paige, a longtime NAACP member, today accused the organization's chairman, Julian Bond, and its president, Kweisi Mfume, of betraying its origins "with their hateful and untruthful rhetoric about Republicans and President Bush."

In an opinion piece published in the Wall Street Journal, Paige told Bond and Mfume, "You do not own, and you are not the arbiters of, African-American authenticity." He said it was "ironic that they would direct this vitriol at a president who has appointed more African Americans to high-profile posts . . . than any other administration."

White House communications director Dan Barlett said Bush "has many friends who belong to the NAACP and respects their proud history of championing civil rights." But he said that "the current leadership of the NAACP has clearly crossed the line in partisanship and civility, making it impossible to have a constructive dialogue."

Paige and Bartlett did not specify the comments that they found vitriolic and uncivil.

In addition to chiding Bush in his speech to the NAACP convention, Kerry also took aim at Cheney over a recent off-color remark on the Senate floor to Sen. Patrick Leahy (D-Vt.).

"And you know, the vice president's having some trouble with the language that he uses to talk to fellow senators these days," Kerry said. "I tell you what, if he needs something to swear about, John Edwards and I are going to give him something to swear about on November 2nd."

Kerry said he and Edwards, the North Carolina senator that Kerry chose last week as his vice presidential running mate, are embarking today on a series of "front porch tours" to talk to average Americans about their concerns.

"Most importantly, we are going to listen to them about the values that matter most to the people of this country," Kerry said.

The Bush administration, meanwhile, spent some of its ammunition today denying rumors of a plan to dump Cheney from the ticket.

White House spokesman Scott McClellan told reporters categorically that Cheney "will be on the ticket."

Cheney, in a C-SPAN interview to be broadcast Sunday, said Bush "doesn't want to break up the team." Cheney said he could not envision any circumstances in which he would drop out and that the president has "made it very clear that he wants me to run again." He said the rumors would be put to rest during the Republican convention in New York from Aug. 30 to Sept. 2.

With the rival campaigns intensifying, the manager of Kerry's election bid, Mary Beth Cahill, announced today that the senator has accepted the schedule of the independent Commission on Presidential Debates for three presidential debates -- on Sept. 30 in Miami, Oct. 8 in St. Louis and Oct. 13 in Tempe, Ariz. -- with one vice presidential debate on Oct. 5 in Cleveland.