Sen. John Edwards, opening his first solo campaign foray as the running mate of Democratic presidential candidate John F. Kerry, pledged today to help bring accountability to the White House after what he described as four years of failed leadership at home and abroad by the Bush administration.

Addressing a crowd in Iowa, Edwards, a first-term senator from North Carolina, cited the response today of British Prime Minister Tony Blair, a staunch ally and friend of President Bush, to a British report on the failures of the country's intelligence service in assessing Iraq's alleged weapons of mass destruction before last year's U.S.-led invasion.

"Tony Blair didn't run from the report," Edwards said. "He didn't try to not acknowledge it. He said, I take full responsibility for the mistakes, because he understands what leadership is."

Edwards also cited the example of president John F. Kennedy during the 1961 Bay of Pigs crisis when a CIA-sponsored Cuban exile force was defeated in an attempt to invade Cuba and unseat communist leader Fidel Castro.

"What we need in the White House is somebody who has the strength, courage and leadership to take responsibility and be accountable, not only for what's good but for what's bad," Edwards said. He said Kerry is that leader, as demonstrated during the Vietnam War when he captained a Navy patrol boat and won medals for valor.

Joining the criticism of the Bush administration today was Sen. Richard Durbin (D-Ill.), who contrasted Blair's acceptance of responsibility for faulty Iraq intelligence with what he described as the Bush administration's refusal to admit mistakes.

"In stark contrast to this administration, today we saw Prime Minister Tony Blair take responsibility for intelligence failures related to the Iraq war," Durbin said in a conference call with reporters. "We know where the buck stops in London. We don't know where the buck stops in Washington."

The Edwards campaign trip -- on a day off for Kerry -- coincided with a series of campaign stops by President Bush in Wisconsin, a state he narrowly lost in 2000.

In a speech in Waukesha, Wis., Bush reiterated his previous defenses of invading Iraq, even though the U.S. Senate's Select Committee on Intelligence reported last week that a purported threat from Iraqi weapons of mass destruction -- the original rationale for the war -- had been exaggerated by the CIA.

"Although we haven't found the stockpiles of weapons of mass destruction, we were right to go into Iraq, and America is safer today because we did," Bush said today.

"I'm working hard because this is going to be a tough campaign," Bush told the crowd of supporters at the Waukesha County Exposition Center. "I know it, and you know it. We take nothing for granted. We got a lot of work to do."

He added: "I'm here to ask for the vote because I have a clear vision and a strategy to win the war on terror and to extend peace and freedom throughout the world." He said he also has a plan to create jobs and a plan to "rally the compassionate spirit of the American people."

"When you give me four more years, America will be safer, America will be stronger, and America will be a better country," Bush said.

As the rival campaigns sought votes in battleground states, the Kerry-Edwards organization launched a new $2 million advertising campaign aimed at black voters and announced that Barack Obama, the Democratic Party's African American candidate for the U.S. Senate from Illinois, will deliver the keynote address at the party's presidential nominating convention in Boston later this month.

"Barack is an optimistic voice for America and a leader who knows that together we can build an America that is stronger at home and respected in the world," Kerry said in a statement.

Obama, the son of a Kenyan father and a white American mother, teaches constitutional law at the University of Chicago Law School. His Republican opponent, Jack Ryan, dropped out of the Senate race last month after embarrassing allegations from his divorce papers were made public. The seat is currently held by Sen. Peter Fitzgerald, a Republican, who is not seeking reelection.