Democratic running mates Barack Obama and Joe Biden appeared together for the first time today before a cheering crowd of an estimated 35,000 supporters gathered in Springfield, Ill., where Obama began his presidential run more than 19 months ago.
"For months, I've searched for a leader to finish this journey alongside me," Obama said. "Today, I have come back to Springfield to tell you that I've found that leader – a man with a distinguished record and a fundamental decency – Joe Biden."
The first term senator praised his more experienced colleague, for his personal fortitude after tragedy and hardship -- and for his foreign policy accomplishments.
"Joe Biden is what so many others pretend to be – a statesman with sound judgment who doesn't have to hide behind bluster to keep America strong," Obama said, introducing his running mate.
Appearing jacketless in the warm August afternoon sun, Biden and Obama talked about their shared visions and their different backgrounds.
"Barack and I come from very different places but we share a common story, an American story," Biden said. "He was a son of a single mom, a single mom who had to struggle to support her son and her kids. ... I was a different. I was an Iirish Catholic kid from Scranton [Pennsylvania] with a father who, like many of you struggled in tough economic times."
Biden immediately began the traditional work of a vice president, serving as the attack dog for the ticket. He hit their Republican rival, Sen. John McCain, R-Ariz., for being out of touch with Americans' economic experience, an area on which McCain made himself vulnerable this week when he could not answer an interviewer's question about how many homes he and his wife own.
"He'll have to figure out which of the seven kitchen tables to sit at," Biden quipped to the appreciative and applauding crowd, which was peppered with newly printed Obama-Biden signs.
"John McCain, and the press knows this, is a friend of mine. He has served in the Senate for 35 years and he wants to do right by America," Biden said, but he then criticized McCain, who he repeatedly called by his first name, for supporting President Bush's policies "95 percent of the time."
Biden, 65, brings immediate heft and foreign policy credentials to a ticket topped by the 47-year-old Obama. The Delaware Democrat first won his job in the Senate more than 35 years ago -- when Obama was only 11 years old -- and has been re-elected five times since.
He's chaired both the Senate Foreign Relations Committee and Judiciary Committee, and raised his profile recently by traveling on a fact-finding mission to war-torn Georgia, where he called for increased U.S. aid to the country and for peacekeeping forces.
The trip underscored his vast foreign policy experience -- something that is lacking from Obama's resume. Biden is also thought to be someone who could hold his own during a vice presidential debate.
McCain called Biden today to offer him congratulations and to pass the same from his wife, Cindy. The two men have served together on opposite sides of the aisle in the Senate for years.
Obama Adviser: 'We're Pretty Good at Keeping Secrets'
After news of the pick leaked to the media late Friday night and early this morning, the Obama campaign sent an e-mail and text message to supporters shortly after 3 a.m. ET, reading in part: "I have some important news that I want to make official. I've chosen Joe Biden to be my running mate."
Appearing on "Good Morning America" today, Obama senior adviser Robert Gibbs touted Biden's foreign policy experience and potential appeal among working class voters.
"We've got someone who hasn't forgotten where he's from, who goes home to Delaware every night on the train, has a working class background from Scranton," Gibbs told ABC News' Kate Snow. "[Biden] has a record of reaching across party lines to get things done not only in foreign affairs -- where he's an undisputed expert -- but somebody who's working to strengthen crime laws in the country, prevent violence against women, and work with Sen. Obama to strengthen fuel efficiency standards in the Congress."
Asked if Biden's extensive Washington experience highlights holes in Obama's own resume, Gibbs disagreed, saying the ticket-mates complement each other.
"I think we've got a great partnership of foreign and domestic policy to keep our country safe and get our economy moving again," Gibbs said. "We think we've got a great pick. ... We've got someone who's ready to partner with Barack Obama to bring change to this country."
While speculation about the veep choice whipped into a fever pitch this week, the frontruners kept mum. Biden, along with Sen. Evan Bayh, D-Ind., and Virginia Gov. Tim Kaine, all received calls about Obama's pick on Thursday, ABCNews has learned.
"Look, we're pretty good at keeping secrets and we pride our campaign on that," Gibbs said. "But what we're not afraid to do today is to talk about our nominee for vice president."
McCain Camp Pounces on Biden Debate Snub of Obama
The McCain campaign wasted little time in hitting Obama's new vice presidential candidate, releasing a new 30-second ad with video of Biden criticizing Obama during a Democratic primary debate.
"I think he can be ready, but right now I don't think he is," Biden told ABC News debate moderator George Stephanopoulos in 2007. "The presidency is not something that lends itself to on-the-job training."
But despite the drama of the early morning text message and the quick McCain attack, ABC's polling director Gary Langer saw little measurable impact in either direction coming from Obama's vice presidential pick.
"As with previous vice presidential picks, Biden looks likely to have little if any direct effect on vote preferences," Langer wrote this morning. "In a new ABC News/Washington Post poll completed [Friday] night, 13 percent of registered voters said having Biden on the ticket would make them more likely to support Obama, while about as many, 10 percent, said it would make them less likely to do so. Most by far -- 75 percent -- said it would make no difference in their choice."
Obama Looks to Washington Insider in Biden VP
Though Delaware is among the smallest states in the country and its three electoral votes are reliably Democratic, Biden brings vast national political experience to the table.
Biden has cast more than 12,500 votes during his long political career. His significant Washington experience fills in a gap in Obama's resume, and yet is something that could work against Obama's outside-the-beltway style campaign.
And, as anyone who has covered Biden can attest, the senator likes to talk. That could be his greatest asset and his greatest liability as the number two on the Democratic ticket.
As a teenager, Biden was able to conquer a bad stutter through public speaking. Forced to give speeches at his Catholic high school, Archmere Academy in Delaware, Biden used the opportunity to work through his affliction.
But Biden's loquacious nature has gotten him into trouble.
Biden has twice run for president -- in 1988 and in 2008 against Obama, among others -- and both times encountered controversy.
Plagiarism charges helped end his 1988 presidential campaign when it became known that Biden had presented elements of a speech by a British politician as his own and without attribution.
Biden explained the scandal this way in an interview with ABC News' Charlie Gibson during the Democratic primaries: "Stupid. My mistake. Born out of ignorance, thinking I didn't have to prepare."
And during the Democratic primaries, Biden was forced to explain himself when he praised Obama as "clean" and "articulate."
"I mean, you got the first mainstream African-American who is articulate and bright and clean and a nice-looking guy. I mean, that's a storybook, man," Biden told the New York Observer last year.
Biden Brings Controversy, Experience to Obama Ticket
During a firestorm of controversy in which his comments were criticized as racially divisive, Obama initially cut his primary rival some slack.
"I didn't take Sen. Biden's comments personally, but obviously they were historically inaccurate. African-American presidential candidates like Jesse Jackson, Shirley Chisholm, Carol Moseley Braun and Al Sharpton gave a voice to many important issues through their campaigns, and no one would call them inarticulate," Obama's statement read.
Biden profusely apologized, and insisted his comments were misunderstood.
"Barack Obama is probably the most exciting candidate that either the Democratic or Republican party has produced, at least since I've been around," Biden said. "He's fresh, he's new, he's insightful."
Biden said he regretted that "some have taken totally out of context my use of the word 'clean.'"
Born Nov. 20, 1942, in Scranton, Pa., the first of four siblings, Biden and his family later moved to New Castle, Del., where the future senator has spent much of his life.
He received a B.A. from the University of Delaware in 1965 and a law degree from Syracuse University in 1968. His first job in politics was serving on the New Castle County Council. His next was a bit bigger.
In 1972, at only age 29, Biden defeated a long-serving Republican to earn a spot in the Senate. The senator-elect turned 30 shortly after the election, qualifying him under the Constitution to take the seat though he was then the fifth-youngest person ever elected to the U.S. Senate.
But the victory would quickly be tainted with tragedy.
Before he was sworn-in, Biden and his wife, Neilia Hunter, whom he married in law school, bought a house in Washington, D.C. They had three young children: two sons, Joseph R. Biden, III (nicknamed Beau), Hunter, and their youngest, a daughter, 13-month-old Naomi.
All of the children were in the car with their mother just outside Washington when a tractor-trailer struck their vehicle, killing Biden's wife and young daughter and seriously injuring his two sons.
Biden contemplated resigning from the Senate, but instead took his first oath of office at the bedside of his sons, who eventually recovered fully.
Since the accident, Biden has made a practice of commuting the 80 minutes from Washington to his home in Delaware almost every night by train. In 1977, Biden married Jill Tracy Jacobs, with whom he has one child -- a daughter, Ashley.
Biden first sought the Democratic nomination for president in 1987, but ran into trouble when it was revealed that remarks he made during a closing statement at an Iowa debate were lifted in large part from a speech by British Labor Party leader Neil Kinnock.
Campaign aides explained that Biden had previously referenced the Kinnock speech with appropriate citation -- but the damage was done, and Biden left the race.
Obama VP Pick Biden Brings Foreign Policy Gravitas
In 1988, Biden suffered two brain aneurysms, both of which required surgery.
Returning to the Senate after the surgery, Biden held on to his slot as chairman of the powerful Senate Judiciary Committee, where he presided over the confirmation hearings of failed Supreme Court nominee Robert Bork, and now-Justice Clarence Thomas.
Biden currently chairs the Senate Foreign Relations Committee, and is vocal on the issue of Iraq, promoting a plan for a "soft partition" of the country into three largely autonomous regions, and working on Senate legislation to start a phased redeployment of troops.
Last year, Biden published a memoir, "Promises to Keep: On Life and Politics," in time for a second White House run.
Despite strong reviews for his debate performances, Biden failed to garner more than 1 percent of the vote in the Iowa caucuses, finishing fifth behind Obama, former Sen. John Edwards, D-N.C., Sen. Hillary Clinton, D-N.Y., and Gov. Bill Richardson, D-N.M.
Biden and his Senate colleague and fellow Democratic presidential contender Sen. Chris Dodd, D-Conn., withdrew from the primary race on Jan. 3, 2008.
Since leaving the presidential race, Biden has focused much of his attention on his seventh Senate run.
He has long been mentioned among political observers as a possible vice presidential candidate, or perhaps even a possible Secretary of State.
Now he will hit the national campaign trail once again, interviewing with the American people for a new job for only the third time in more than 30 years.
Biden brings with him a long resume and the gravitas of a senior statesman -- a potent mix Obama chose over a field of younger, but perhaps less-experienced contenders.
ABC's Sunlen Miller and Sara Just contributed to this report.