Of all the events that have shaken the Soviet bloc in 1989, none is more fraught with history -- or more implausible -- than the polite encounter that will take place this week in Vatican City. There, in the spacious ceremonial library of the 16th century Apostolic Palace, the czar of world atheism, Mikhail Gorbachev, will visit the Vicar of Christ, Pope John Paul II. Before delivering formal speeches in the presence of their entourages, the two East Europeans will sit down alone to chat in Russian without interpreters.
The moment will be electric, and not only because John Paul helped...