WASHINGTON, DC - America's opening to China by Richard Nixon and Henry Kissinger in 1971-1972 was a historic breakthrough. Less famous, but of equal importance, was the next major step, taken by Jimmy Carter exactly 30 years ago, establishing full diplomatic relations between China and the United States. Without this action, announced on December 15, 1978, US-China relations could not have moved beyond a small, high-level connection with a limited agenda.