Joe Biden's son Beau, the Attorney General of Delaware and a soon-to-deploy National Guard Captain, introduced his dad tonight. Beau gave a moving first-person version of the story we've heard so many times since last weekend, about Joe's dedicated single fatherhood after his first wife and baby daughter died in a car crash that left his two sons badly injured. Senator Biden, who had been elected but not yet sworn in at the time of the accident, took his oath of office in Beau's hospital room and commuted home to Delaware by train every night after finishing his work in the Senate.