The Senate has unanimously declared John McCain a natural-born citizen, eligible to be president of the United States. That is the good news for the presumptive Republican nominee, who was born nearly 72 years ago in a military hospital in the Panama Canal Zone, then under U.S. jurisdiction. The bad news is that the nonbinding Senate resolution passed Wednesday night is simply an opinion that has little bearing on an arcane constitutional debate that has preoccupied legal scholars for many weeks.