US Democratic presidential candidate Barack Obama has praised his
newly-named running mate, fellow-Senator Joseph Biden, as a leader
ready to step in and be president.
Obama introduced Biden as his vice presidential pick in their first joint appearance as running mates at a rally in Springfield, Illinois, Obama's home state.
Obama said Biden is a powerful critic of the Bush Administration's foreign policy and a leader uniquely suited to put America on the right track.
In his remarks, Biden immediately went on the attack against Republican candidate John McCain. Biden repeatedly linked McCain to fellow Republican President George Bush and said the nation cannot afford four more years of the same policies if McCain wins.
Obama announced his pick for vice president on his Web site early on Saturday.
The McCain campaign responded by releasing a television ad that included previous remarks by Biden in which he said Obama is not ready to be president.
The 65-year-old Biden is chairman of the Senate Foreign Relations committee. He has been in the Senate for more than 35 years.
The Democratic National Convention opens in Denver, Colorado Monday and will formally nominate the Obama-Biden ticket.
Obama passed over several potential running mates, including Senator Hillary Clinton -- his main rival for the Democratic Party's nomination.
Senator Clinton on Saturday expressed support for the ticket, describing Biden as "an exceptionally strong, experienced leader and devoted public servant".
After a long and bruising nominating contest, Clinton has worked with her former rival to unify the Democratic Party and convince her supporters to help put Obama in the White House.