Presidential candidate Barack Obama has chosen Delaware Senator Joseph Biden as his vice presidential running mate, saying he is the right partner to put the United States back on track.
Introducing his running mate at a rally in Springfield, Illinois tonight, Mr Obama said Mr Biden was a leader offering a “rare mix” of change and experience.
“For decades, he has brought change to Washington, but Washington hasn't changed him...He is uniquely suited to be my partner as we work to put our country back on track.”
Speaking at the rally, Mr Biden said the next president of the United States would have an "incredible opportunity" not only to change the direction of America, but to change the direction of the world.
Criticising the Bush administration on energy policy, on tax breaks for companies who were "shipping our jobs overseas" and on the war in Iraq, Mr Biden said it was "not sloganeering" when he said the US could literally not afford four more years of the same.
Mr Biden said President Bush had been responsible for a foreign policy that had "shredded" its alliances and sacrificed its moral standing around the world.
Mr Biden (65), the chairman of the Senate Foreign Relations Committee, is one of the most knowledgeable Democrats on foreign policy - an area where Mr Obama, a first-term senator from Illinois, has been criticised as inexperienced.
The candidate for the vice presidency joined Mr Obama today for their first campaign event in Springfield, Illinois, the home town of President Abraham Lincoln and the place where Mr Obama launched his White House bid last year.
Addressing supporters, Mr Obama said he had found a leader who is ready to step in and be president and that Biden was the right partner to put the US back on track.
Mr Obama had earlier ended days of speculation by announcing the decision on his website, featuring a photo of the two, and his campaign sent a text message and e-mail to supporters.
"Barack has chosen Joe Biden to be his running mate," the announcement said. "Joe Biden brings extensive foreign policy experience, an impressive record of collaborating across party lines, and a direct approach to getting the job done."
Mr Biden, a Roman Catholic originally from the battleground state of Pennsylvania, will bring not only foreign policy expertise to the ticket but strong working-class roots.
That could help Mr Obama connect with the blue-collar voters he has failed to attract in the run-up to the November 4th election against Republican John McCain. Mr Obama and Mr McCain are neck and neck in opinion polls.
Mr Biden's 2008 presidential bid fell flat but he was a forceful and aggressive debater, firing off some of the toughest criticisms of Republican president George W. Bush.
The choice of Mr Biden, who was first elected to the Senate in 1972, indicates Mr Obama was more interested in filling gaps in his foreign policy experience than in finding someone who could reinforce his message of bringing change to Washington.
Mr Biden's record includes outspoken opposition to US government support for South Africa's apartheid system in the 1980's, agitation from the Senate for stronger US intervention in the Balkans in the 1990s and close involvement with US policy on Iraq, Iran and Pakistan.
Mr Biden voted in 2002 for a resolution that authorized the invasion of Iraq after failing to secure support for another resolution to that would have allowed military action only after diplomatic efforts had been exhausted. Mr Obama was not in the Senate then, but spoke out against the invasion.
Tonight, Mr Obama said the US could not afford another four years of failed foreign policy.
Senator Hillary Clinton, beaten by Mr Obama narrowly in a bitter struggle for the Democratic nomination, welcomed the selection of Mr Biden, who she described as "an exceptionally strong, experienced leader and devoted public servant".
"Senator Biden will be a purposeful and dynamic Vice President who will help Senator Obama both win the Presidency and govern this great country," she said.
The choice of a running mate can reflect on a candidate's judgment and offer hints of the qualities valued in a crucial adviser, although history has shown it is unlikely to have a major impact on the election between Mr Obama and Mr McCain.
Mr McCain (71), a Vietnam War veteran and long-time senator from Arizona, has yet to name a running mate.
The McCain campaign quickly launched a television ad using a clip from a Democratic presidential candidates' debate earlier this year in which Mr Biden said he did not believe Mr Obama was ready to be president and praised Mr McCain. After the Springfield rally Obama and Biden were to make a tour of some key battleground states, including Iowa and Montana, as they head to the Democratic Party convention that opens on Monday in Denver.
On Thursday, Mr Obama will formally accept his party's nomination as its presidential candidate, making history as the first black to do so.
While Republicans have tried to depict Obama as a celebrity, Biden has a more down-to-earth image. "I'm not a superstar," Mr Biden said in an interview in December.
Additonal reporting: Reuters/Bloomberg