It makes sense

Although, I was rooting for Clinton, I can understand Obama's reasoning on choosing Biden to be his running mate.

Biden is strong in area's that Obama lacks experience. Biden has over 30 years of experience in the Senate, and most importantly, has the most experience in foreign policy or defense, much like Obama's presidential rival, McCain. And with Georgia under attack by Russia, foreign policy has come to the forefront for the two presidential hopefuls.