Washington, D.C. PETER LANSING was talking about greatness and Ronald Reagan, but was having a little trouble finding all the right words as he stood outside the U.S. Capitol one evening last week. "I want to pay my respects to a great man, probably the greatest president in my life," said Lansing, an electrical engineer. At 46, Lansing has now lived through parts of 10 presidential administrations, including Dwight Eisenhower and John F. Kennedy. But as he waited to walk by Reagan's flag-draped coffin in the Capitol rotunda, he insisted Reagan was far above everyone else. Why? What is the...