Democratic presidential candidate John Kerry (search) on Tuesday announced his choice of John Edwards (search) — his Senate colleague and primary campaign rival — to be his vice presidential running mate.

"I am pleased to announce that with your help, the next vice president of the United States of America will be Senator John Edwards from North Carolina," Kerry told a rousing group of supporters in Pittsburgh.

Kerry said the former presidential hopeful displayed the "guts and determination and political skill in his own race for president of the United States" and that his life has "prepared him for leadership." It's the first time since 1960 that two senators have been on a ticket for the White House.

"John Edwards and I are going to fight to build one America for all Americans," Kerry continued, referring to Edwards' own campaign theme of trying to bridge the "great divide" between classes in America.

Kerry said he had earlier spoken to a "number of talented and decent Americans" who were also in the running for vice president on his ticket.

"Each of those individuals — and I mean this — would make a great vice president and indeed in their own right could lead our country," Kerry said. "But I can choose only one running mate and this morning, I have done so. I have chosen a man who understands and defends the values of America. A man who has shown courage and conviction as a champion for middle-class America and for those struggling to reach the middle class."

As for Edwards' reaction, he issued a statement saying he's "honored" and "humbled" to be asked to join the ticket.

Kerry is "a man of strength, character and courage," Edwards said. "He has a vision for our country that will make life better for all Americans — those in the middle class who struggle every day to make ends meet, and the millions of Americans fighting to enter the middle class.

"I look forward to seeing all of you in the days ahead and talking to the American people about the next president of the United States."

Kerry earlier sent out an e-mail to supporters, telling them of his decision.

"I can't tell you how proud I am to have John Edwards on my team, or how eager I am for the day this fall when he stands up for our vision and goes toe-to-toe with [Vice President] Dick Cheney," Kerry said in the e-mail.

Kerry will later give a speech in Indiana, then will return to his wife's family farm and mansion in Pittsburgh.

On Wednesday, Kerry and his newly-chosen sidekick are scheduled to be out on the campaign trail together in Ohio — perhaps the most critically important battleground state and one that serves as a bellwether for the rest of the country.

"I welcome Senator Edwards on the ticket … I look forward to a good spirited debate," President Bush said.

Republicans are already downplaying the decision, saying Edwards won't help the ticket too much.

Meanwhile, the Bush-Cheney re-election campaign announced the release of the campaign's newest television advertisement, which features Kerry's first choice for vice president, Sen. John McCain (search), R-Ariz. In the ad entitled "First Choice," which will air on national cable and in selected local markets, McCain discusses his support for Bush.

"Once McCain was out of the picture, I think Edwards really was the first choice," said FOX News contributor and Democratic strategist Susan Estrich. "I think he [Kerry] just needed to take his time and come to the point where the two [Kerry and Edwards] were comfortable with each other. It was the logical choice."

Bush-Cheney campaign Chairman Marc Racicot released a statement welcoming Edwards into the race.

"Senator Edwards is a committed liberal and spirited messenger for his party in an election that will decide the course our nation takes in turning a recovery into prosperity for all Americans, and in the War on Terror," the statement said. "There will be vigorous debates about these issues in this election."

The Others

Kerry had given serious consideration to Rep. Dick Gephardt of Missouri, Gov. Tom Vilsack of Iowa, retired Army Gen. Wesley Clark, Sen. Evan Bayh of Indiana, Sen. Joe Biden of Delaware and Sen. Bob Graham of Florida.

Delegates will be asked to formally nominate his pick at the Democratic National Convention in Boston on July 26.

"This is a ticket that can excite, motivate and, most importantly, defeat George Bush and Dick Cheney in November," Gephardt said in his statement on Edwards. "I will continue to work hard for their election and look forward to campaigning with them and for them in the months ahead in our efforts to move America forward."

Added Vilsack in a statement: "The last few weeks of speculation have been flattering and a great compliment to the state of Iowa. [Wife] Christie and I are enthusiastic to do all that we can to help John Kerry and John Edwards win in November."

Former Vermont Gov. Howard Dean, who was the front-runner in the Democratic race until has campaign imploded, also chimed in. "John Edwards is a smart choice for John Kerry's running mate ... I will be working hard over the next few months to get them both elected," Dean said in a statement.

Edwards outlasted all but Kerry in the Democratic primary fight and is the favorite of many party regulars.

"I like John Edwards a lot and I think he'll bring a lot to the ticket. It will help him in places like Arkansas where I'm from," said former President Bill Clinton. "He's really smart, he's really articulate and he works like crazy."

Asked if wife Hillary had talked with Kerry about possibly getting on the ticket, Clinton responded: "As far as I know, no" talks with Kerry ... we're excited, we just want to help and we'll do whatever we can."

Added former Vice President Al Gore: "This team combines John Kerry's courage and record of outstanding leadership and John Edwards's inspiring struggle on behalf of middle-class Americans and those working to reach the middle class."

The Kerry campaign has a staff of more than a dozen standing ready to serve the vice presidential nominee.

Edwards Has 'Zip'

Edwards is the favorite of many Democratic activists because of his youthful good looks, a self-assured manner and a message that focused on President Bush's "two Americas" — one for the wealthy and another for everybody else.

"What John Edwards will bring is an energy that surpasses that of the Democratic Party right now," Richard Goodstein, a former campaign adviser to Al Gore, told FOX News on Tuesday.

And Edwards' trial-lawyer background can't hurt the ticket either, Goodstein said.

"Edwards can stand up and say, 'I leave my career — yes I haven't been in public office very long — I leave my career standing up for the little guy,'" Goodstein continued.

But Edwards alone won't bring Kerry to the White House, he added.

"Honestly, at the end of the day, that's not what people are going to vote on … what it comes down to is John Kerry versus George Bush."

But others express concern that Edwards, whose only political credential is a single term in the Senate, lacks the experience in international affairs, particularly in wartime, to be a credible candidate to assume the presidency in the case of death, resignation or removal.

"Does Edwards bring gravitas to the ticket — someone who can step right in and take over as president? I don't think so," said Fred Barnes, co-host of FOX News' "The Beltway Boys." "But zip and excitement — he has it."

Edwards, 51, seldom criticized Kerry or any of the other Democrats while running a generally positive campaign. The two had few major policy disagreements — both supported the decision to go to war in Iraq, for example, and both voted against the $87 billion package for Iraq and Afghanistan.

Fox News' Carl Cameron and The Associated Press contributed to this report.