If you were to list the Americans most critical in facilitating the collapse of the Soviet Union, the name of Bill Clark, or "Judge Clark," might not be on your list -- but it should be. Many of us know that no president was as crucial to that collapse as Ronald Reagan, but few know that no adviser was as crucial to Reagan in that endeavor as Bill Clark. I know this well. I was blessed to become Clark's biographer, and for about 12 years, dating back to when we first met in August 2001, I spent many hours and days and phone calls with this truly great man. This great man and exceptionally kind and decent person died at his California ranch on Saturday at the age of 81.

Clark succumbed to a long illness delivered by the merciless hands of Parkinson's disease, which had also taken his dear father decades ago. "The good Lord gave Parkinson's to saints like my father and Pope John Paul II," said Clark, a devout Catholic who saw everything, including suffering, as part of God's providence. "Now he's gotten around to giving it to sinners like myself."

Clark saw this (and more) as his "much deserved" cross to bear -- when, in fact, nothing so unpleasant was ever deserved by Bill Clark. That likewise included the humiliation that a young senator from Delaware named Joe Biden delivered to Clark in February 1981 during Clark's sensational confirmation hearings for the position of deputy secretary of state. (Click here to read more.) Clark endured that, too.

Regardless, Bill Clark suffered Parkinson's for a longer time than any of us imagined or wished. Like the Alzheimer's disease which ultimately felled Ronald Reagan, Clark hung on to life as long as he could muster.

That said, Bill Clark would certainly agree he was headed for a better place, even when he seemed in no hurry to get there. As I look at the inside flap of my biography of Clark, I see that all the relationships detailed therein -- Clark's cherished friendships -- involved people who have since passed on. Beyond his wife and parents and family, there was Reagan, Cap Weinberger, Lyn Nofziger, Clare Boothe Luce, Bill Casey, Al Haig, and even figures like Margaret Thatcher and John Paul II. They're all gone. Bill Clark is reunited with them all at long last.

Among those names, one of the most moving moments I had with Clark came one day while he was reading a finalized section of the biography; it noted the death of one of his best friends, Cap Weinberger. As he slowly read, line by line, word after word, the stoic, manly Clark suddenly started to sob, bursting into tears. I had never seen him like that before. "I'm sorry," he apologized to me, wiping tears from his faith. "You'll see what it's like to be old someday."

As Weinberger had lain dying, he had his wife call Clark so he could say a final goodbye. Clark's parting words to Weinberger, told to Weinberger through tears at that moment, were favorites of John Paul II and of Scripture. "Be not afraid, Cap. Be not afraid."

Bill Clark was a man unafraid. He fearlessly joined Ronald Reagan in taking down a truly Evil Empire, with standing barbs and attacks from all corners, even here at home. For that alone, we owe him our gratitude and remembrance.

Dr. Paul Kengor is professor of political science and executive director of The Center for Vision & Values at Grove City College. His books include The Judge: William P. Clark, Ronald Reagan's Top Hand (with Patricia Clark Doerner) and The Crusader: Ronald Reagan and the Fall of Communism.