DETROIT, SEPT. 19 -- During his 246 hours in the United States, Pope John Paul II made his positions unmistakably clear. But when Shepherd One left here tonight and disappeared into the cold Canadian darkness, what remained were questions, contradictions and an image that was in a sense Reaganesque: People liked the pope more than they accepted parts of his message.

The trip was beyond classification as success or failure, it was such an odd mixture of moralism, pageantry, cultural expression, emotion, debate and music. When Aretha Franklin sings spirituals in the streets of Detroit, when Pete Fountain's plaintive clarinet ascends the scale heavenward in New Orleans, when an armless young man in Los Angeles captures the indomitable spirit of youth by playing the guitar with his bare feet -- it is hard to speak too critically of something wrapped in such overwhelming beauty.

Yet the crowds were smaller than expected at every stop -- in part because of official warnings to stay away -- and often there was a disconnection between what many of America's 53 million Roman Catholics wanted to hear and what the pope chose to say. They had one agenda; he had another. They wanted to know whether the Vatican would help them deal with the moral issues that white, middle-class America is struggling with, but he basically said that their issues were, if not irrelevant, at least resolved.

He became, in the words of one frustrated priest, a "sort of Dr. No," -- no to birth control, divorce, abortion, ordination of women, marriage in the priesthood and homosexuality. No to dissent from Roman Catholic doctrine and teachings in general. This should not have come as a surprise -- he has always been unbending on those issues -- but it was cause for some disappointment.

But John Paul had another message, the hallmark of his papacy. From his arrival speech in Miami 10 days ago to his departure address at the airport here tonight, his dominant theme has been the relationship between the American gifts of wealth, technology and freedom and the universal causes of human dignity and social justice. Popes rarely lead, one Catholic official said, but on this point, John Paul is a leader.

Although his message was religious, it was also, indisputably, social and political. He defined it one last time during his departure speech tonight: In a land of material richness and political freedom, "the ultimate test of your greatness is the way you treat every human being, but especially the weakest and most defenseless ones."

That reference included more than the unborn. It embraced as well the new immigrant poor, refugees from Mexico, Central America, Asia and the Caribbean whose populations have swelled in many of the cities on this second American tour: Miami, San Antonio and Los Angeles in particular. These newcomers have brought to this modern country a Third World church more in tune with the preachings of a highly traditional pontiff, and he often seemed most comfortable when addressing them and their issues, especially in Spanish.

It is appropriate that he is more fluent in that tongue than in English. But in either language, he spoke with just enough ambiguity to be able to avoid political controversy. This was especially true in San Antonio, where his praise of the "courageous men and women" who have helped feed and shelter undocumented immigrants was interpreted as an endorsement of the Sanctuary Movement, which shelters illegal aliens. Not really, his spokesman said the next day -- he never used the word "sanctuary," and he never encouraged anyone to disobey the law of the land.

The pope also struck the right chords with black Catholics in New Orleans and teen-agers and elementary schoolchildren in Los Angeles -- even, in the end, with the men dying of AIDS whom he encountered inside a church in San Francisco. What these audiences had in common was that all they asked of the pope was love and respect. To them, he was no longer a stern father but a loving uncle.

Some audiences asked him to listen as well. And even when he did not like what they had to say, he made clear that he had heard. After the Rev. Frank J. McNulty urged him to reconsider the tradition of a celibate priesthood, among other things, the pope ad libbed, "I'm reminded of the song, 'It's a Long Way to Tipperary.' " No minds would be changed, but hearts were won.

To Joaquin Navarro-Valls, the pope's chief spokesman, the trip was a success precisely because of the pope's ability to play both roles. This brought what Navarro-Valls called an "internal cohesion" to the Catholic Church in America by balancing moral law with mercy.

That is far easier for him to say than for Catholic clergy here to interpret. The key religious dialogue of the visit came during the pope's meeting with American bishops in Los Angeles, where he termed it a "grave error" to assume that someone can dissent from church doctrine and be a good Catholic.

A few hours after the four-hour private meeting with the pope, Archbishop Edward R. Head of Buffalo was trying to work this one out in his mind.

"We must define what we mean by dissent," he said. "If I'm the father of four children all under five years of age, and I'm on unemployment . . . it becomes awfully difficult to follow church law on birth control. A little bit of free will has been removed in such cases.

"Every Catholic doesn't have to be a saint -- none of us are saints. We're not planning to throw anybody out of the church. There's always a place for them -- always," he added.

The pope has a way of bringing issues to the surface, even if he does not resolve them. On almost every occasion during this trip, he said exactly what he wanted to say, regardless of how it might be taken by his audience.

Thus in Miami, while telling Jewish leaders he supported Israel's right to exist, he also spoke of the need for a Palestinian homeland. And at a convention of American Indians in Phoenix, he praised a California missionary, Fray Junipero Serra, who is regarded by many Indians as an accomplice to Spanish conquerors who killed many Indians and stamped out their cultures. The pope maintains that Serra was a champion of Indian rights, so he was unhesitant to sing the missionary's praises even to a crowd that was having none of it.

But the Indians loved John Paul anyway, even despite the fact that his accent and the poor acoustics at the Phoenix coliseum made it difficult to understand much of what he was saying. He gave 45 speeches in 10 days, countless thousands of words in all, but at times like this, and perhaps ultimately, his presence transcended words.

There was no way the pope was going to resolve the conflicts of American Catholicism -- he did not want to. He sees himself as a symbol not only of peace, but of contradiction. On the penultimate day of the journey, during Mass at San Francisco's Candlestick Park, Pope John Paul II seemed to be placing his evangelical mission in perspective. "It should not surprise us," he said, "if in our efforts to be faithful to Christ's teachings, we meet with criticism, ridicule or rejection."

But the pope did not leave the United States on a note of rejection. He left with the sights of Polish Hamtramck and the sounds of black Detroit, marveling, as anyone might, at modern America's diversity and the worth of every person.

"This is the dignity of America," he said, "the reason she exists."