[BLOG: Hillary Clinton's reaction to selection]
The selection of the 65-year-old Biden is seen striking a balance on the ticket by picking a a seasoned congressional veteran well-versed in foreign policy and defense issues.
Obama announced the pick on his Web site with a photo of the two men and an appeal for donations. A text message went out shortly afterward that said, "Barack has chosen Senator Joe Biden to be our VP nominee."
Biden's three decades in the Senate give him more than ten years seniority over Republican candidate John McCain. Biden chairs the Senate Foreign Relations Committee.
Biden has a generally liberal voting record and a reputation as a long-winded orator who speaks his mind.
Obama and Biden plan their debut today outside the Old State Capitol in Springfield, Illinois.
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