In a move that will shore up his foreign policy and national security cred, Barack Obama has selected veteran Delaware Senator Joe Biden to be his running mate, according to a Associated Press story filed here

Biden is a widely respected figure in Washington, with a reputation for mastery of the intricate details of foreign policy issues. He is known for a quick wit, a sometimes equally quick temper, and a competitive and sharp-elbowed political style harnessed to a well-earned reputation for long-windedness. He has previously mounted two notably unsuccessful bids for president.

As a political matter, Biden will help immediately to bolster Obama on national security, an area where he has come under increasing attack from Senator John McCain, who will be nominated at the Republican convention next month. Also Biden is a Catholic with blue-collar roots who may help Obama appeal to working class Democrats, who overwhelmingly supported Hillary Clinton in the primaries.

On the negative side, Biden sharply criticized Obama during the brief period when Biden was contending for the nomination last year, saying the party's soon-to-be official nominee was not yet prepared or qualified to be president. Biden has also political baggage of his own, including a flap over a speech he plagiarized from a British political leader while running for president in 1988, and some embarrassing moments on the campaign trail, as when he snapped at a voter during that same race, accusing the man of being stupid - in front of a video camera.

At a time when McCain has been cutting away at Obama's once-substantial lead by attacking his inexperience on national security, however, Biden's greatest strength is to offer substance and experience on the issue the Republicans are trying to use to define the race. Voters still identify domestic economic concerns as their top priority, and Biden's presence on the ticket may give Obama more breathing room to focus his attention there.