With Justice David Souter's 65th birthday last month, the only member of the Supreme Court who is under retirement age is 56-year-old Justice Clarence Thomas. While Supreme Court justices have proven the adage that with age comes wisdom, there is no denying that with age also come ailments: Three of the four justices over the age of 70 have suffered from cancer. And, on Monday, it was revealed that Chief Justice William Rehnquist, 80, has joined this group, with a diagnosis of thyroid cancer. The severity of Rehnquist's illness is unknown, but he expects to be back at work on...