Last night Barack Obama said, "If John McCain wants to have a debate about who has the temperament, and judgment, to serve as the next Commander-in-Chief, that's a debate I'm ready to have."

This morning John McCain confirmed the problem to which Obama alluded. His choice of Alaska Governor Sarah Palin as his running mate is precisely the impulsive, risky sort of gamble that is a McCain trademark. He saw himself as losing, especially after the...