It may seem like an odd choice for a presidential candidate of change to choose a veteran politician as his running mate but Joe Biden's selection by Barack Obama makes good political sense. The senator from Delaware brings several advantages that address Sen. Obama's perceived weakenesses.

To those who think that Barack Obama's candidacy is a lightweight craft sailing in rough seas, Sen. Biden brings a heavy keel of experience to trim the Democratic boat.

Now 65 years old and a senator since 1973, he more than makes up for Mr. Obama's alleged shortcomings in experience, particularly in the area of foreign relations. As chairman for the Senate Foreign Relations Committee, Mr. Biden knows as much or more than anyone in Congress about foreign affairs, including the presumptive Republican nominee, John McCain.

He also serves on (and has chaired) the Senate Judiciary Committee, which has put him at the center of Supreme Court nomination hearings.

In introducing his VP choice in Illinois on Saturday, Mr. Obama said he searched for a leader who is ready to step in and be president -- and on that score he has clearly succeeded. He has picked a vice presidential nominee who is exceptionally well versed on the issues and has compiled a record of accomplishment wide enough to encompass being tough on crime and caring about how ordinary families pay for college tuition.

While Mr. Biden initially supported the Iraq invasion, he became disenchanted with the administration's approach -- which indeed is what the American people came to. The point is that he can't be dismissed as someone who is reflexively against American use of force if it is judiciously applied.

To be sure, any politician with a long record of public service has made mistakes (his first run for president in 1987 floundered amid allegations of plagiarism) and the voters will hear about those anew. He also is famously long-winded. But his past mistakes are not fatal and when he speaks at length it is often because he has something important to say. As well as hot air, he does generate a lot of personal affection -- and not only among his constituents. Even Sen. McCain calls him a friend.

In Sen. Biden, the Democrats can make a pitch for blue-collar voters, whom Mr. Obama has found hard to win over, some still holding a grievance over the defeat of Sen. Hillary Clinton. For all his accomplishment and polished manner, Mr. Biden has authentic working-class roots from his boyhood in Scranton, Pa., and that experience has made him the Democrat he is.

What the Democrats needed on their ticket was someone who has the taste for a fight and who can bring energy to that task. Mr. Obama has shown a reluctance (or an inability) to really mix it up.

Sen. Clinton would have done that for the ticket, but she also would have brought a lot of negatives too. Sen. Biden doesn't have that baggage and will be a happier warrior while adding sinew to the arguments the Democratic ticket must make to win the White House.

Mr. Biden will not bring a big state with him (unless his crossover influence in Pennsylvania is decisive), but Mr. Obama has chosen well. Mr. Obama has the gift of articulating the mood of the moment in soaring oratory and he still carries the hopes of a new generation. But he's also smart: He knows that it can only help to have a seasoned campaigner such as Joe Biden at his side.