Christopher Reeve, the actor who became famous as Superman, died Sunday. He was 52.

Reeve was paralyzed by a horseback riding accident in 1995. More than his on-screen roles, it was the accident and the courageous way he never gave up the hope of one day walking again that best defines Reeve.

He became a dedicated and forceful activist for research into spinal cord injuries and for investing in new medical technologies.

Reeve was a powerful advocate for stem cell research, a contentious issue in this year’s presidential campaign. He criticized President Bush for limiting federal funding and slowing the pace of research.

Reeve was right. Stem cell research, still in its scientific infancy, holds great promise for millions of people who suffer from spinal injuries and disease. The government shouldn’t be an impediment; but should, instead, help facilitate research into new medical discoveries.

Despite his near-fatal accident, numerous bouts with infections and dependence on a breathing tube to live, Reeve never gave up hope, never quit. He was willing to take any chance and to advance any cause that might one day restore his broken body and those of others. That legacy of courage and determination will continue.