"I was the first Western journalist inside the KGB headquarters in 1990," a journalist named Eric Margolis told PBS, recounting his venture into the heart of the Soviet Union's once-fearsome intelligence service, which had just collapsed along with the empire that it served. "The generals told me that the Vatican and the Pope above all was regarded as their number one, most dangerous enemy in the world," he said. Mikhail Gorbachev, the final Soviet leader, once said of the Cold War's peaceful end, "It would have been impossible without the pope."

Pope John Paul II, who led the Catholic Church from 1978 to 2005, was also a major player in global politics, and not just in his celebrated role helping to end the Cold War. He intervened to address crises within Catholic-majority countries, some of them bloody, strengthened the church's hold in the developing world, and engaged with the leaders of other global religions.

Pope Benedict XVI, who Monday announced that he will resign at the end of the month, never quite met the bar that John Paul II set in papal political leadership. That is in part a function of how much the world has changed in the last few decades; during John Paul's tenure, Catholic-majority nations in Europe and Latin America faced enormous political crises that they generally don't today. But as Benedict's legacy takes shape, naturally drawing contrasts with his predecessor, his record appears to be comparatively weak on political leadership, global travel and outreach to other faiths.

John Paul II took 104 official trips outside of Italy, traveling widely across every continent. His nine-day trip to his native Poland in 1979, where he delivered his famous "be not afraid" speech, helped inspire the country's Solidarity movement. Cold War historian John Lewis Gaddis credits John Paul's trip for Solidarity's emergence and ultimate triumph over communism; fellow historian Timothy Garton Ash once said, "Without the Pope, no Solidarity. Without Solidarity, no Gorbachev. Without Gorbachev, no fall of Communism."

John Paul II also helped mediate a 1984 peace treaty between Chile and Argentina; both governments credit him personally with preventing war. He became a minor hero of the anti-apartheid struggle in South Africa, credited by Mandela for having "deeply inspired" him. He pressured, and personally lobbied, Chilean dictator Augusto Pinochet to allow greater democratic rule, which he did the next year. He went on similar missions to Haiti and Paraguay, publicly criticizing his host governments for their abuses. As part of his aggressive outreach to other faiths, he became the first pope to visit the Auschwitz concentration camp and the first to pray in a mosque.

Benedict, due in part to his older age, in part to his shorter tenure and in part to temperament, traveled far less widely. He took only 24 trips outside of Italy, most of those within the Western world. “He had a hard act to follow in John Paul, who was bigger than life," Rev. Thomas Reese, a Catholic writer, told The Washington Post. "Benedict suffered by comparison because he was much more shy, he wasn’t an actor, he preferred to write books and issue encyclicals rather than travel. And he was old when he was elected."

Still, a pope who wished to model himself after John Paul II's celebrated political legacy might have found ample opportunities. He might have pressed the leadership in Catholic-majority Cuba for reform. He might have attempted to mediate political conflicts in Catholic-heavy Central Africa, particularly in the long-troubled Democratic Republic of Congo. He might have found cause in working with Muslim-majority countries such as Turkey or Egypt, particularly as political Islamism rises, toward fair treatment for Christian minorities (though Egypt's Christians are Coptic, rather than Catholic). He might have preoccupied himself with the fault line between Christianity and Islam in sub-Saharan Africa, where many Christians are Catholic. Since Benedict took over in 2005, religious and political conflicts have blurred in countries such as Nigeria, Côte d'Ivoire and Sudan, none of which he ever visited.

Benedict's political efforts, like his travels, were relatively modest. He was embroiled by controversies and social debates within the Western Catholic world, over a child sex abuse scandal and issues such as same-sex marriage and contraception. His position on HIV/AIDS, which is ravaging African societies, many of which are also heavily Catholic, has troubled the church's outreach there. He said in 2009, "If there is no human dimension, if Africans do not help, the problem cannot be overcome by the distribution of prophylactics: on the contrary, they increase it." And his discussion of Islam as a competitor of Catholicism, rather than a partner as John Paul II had described it, did little to advance interfaith dialogue.

Whoever takes over after Benedict will face these same challenges and the same daunting comparisons to John Paul II. Whether he meets them or not – and, unless the Vatican changes its rules forbidding female popes, the next Catholic leader will be a "he" – may help to determine whether John Paul II's political activism becomes the norm for a pope or the exception.