Young and vigorous when he assumed the papacy, Pope John Paul II has been a picture of pain and suffering in recent years, a bent figure with trembling hands and quavering voice.

Yet the 84-year-old pontiff appears intent on playing out his agony for all the world to see — sending out a message of dignity, courage and acceptance of the trials of life.

As John Paul was rushed to the hospital for the second time in three weeks with breathing problems Thursday, the Vatican (search) (newspaper suggested he was sharing in Christ's suffering and said "the bed of pain" has become "the cathedral of life."

Vatican Cardinal Renato Martino (search) called it "a real example of how to accept human suffering."

It is a message that top aides have been making as a pope once called "God's athlete" has steadily deteriorated physically over the past decade, burdened by Parkinson's disease (search) and crippling knee and hip ailments.

Some question, however, how long a pope who once skied and hiked can guide the 1 billion Roman Catholic faithful when his voice is silenced and he can no longer walk.

The world has watched the pope's frailties, and several images stand out.

During a pilgrimage to the French shrine at Lourdes (search) in August he trembled and asked an aide to help him, calling out in his native Polish. Already during a 1999 trip to the former Soviet republic of Georgia, cardinals formed a buffer to shield the shaking pontiff from the wind.

"It is a representative image, rather beautiful, of what is solidarity in the church," Vatican Radio said at that time.

The power of suffering may be alien to many, but the concept was the core of Mel Gibson's film "The Passion of the Christ," a box office success around the world. Several top Vatican cardinals endorsed the film. John Paul viewed it, though the Vatican denied that he expressed his approval.

The pope's views on illness and suffering have another side to them, as he pointed out in his recent message written for Lent that included a forceful condemnation of euthanasia (search).

"What would happen if the people of God yielded to a certain current mentality that considers these people, our brothers and sisters, as almost useless when they are reduced in their capacities due to the difficulties of age or sickness," the pope said.

The commandment "Thou shalt not kill," he said, "applies even in the presence of illness and when physical weakness reduces the person's ability to be self-reliant."

For papal biographer George Wiegel (search), the pope's suffering is a reminder that "especially in the West, we live in a world in which we think the old and the suffering are disposable."

"The pope is saying there are no disposable people. That is a very important message for the whole world, not just for Christians," he told The Associated Press.

Inevitably, the pope's physical decline raises questions about how long he can steer the church, particularly as his speech deteriorates.

The much-traveled John Paul has already been cutting back on his foreign trips, with only an August pilgrimage to a Catholic youth festival in Germany on the schedule this year. While keeping up with his audiences, even during his recent convalescence, he has been leaving more and more of Vatican business to aides.

When John Paul faltered at Lourdes, Belgian Cardinal Godfried Danneels (search) found it an "extremely moving" moment but also said he found the pope "seriously weakened."

But Cardinal Javier Lozano Jose Barragan (search), a Mexican based at the Vatican, said it was enough for the pope to express himself in writing if he can't talk.

"For important decisions regarding serious problems and aspects of the Church, which have to be taken daily, it is important for him to express himself and even if he cannot speak he can write," he said.