On his visit to Mexico, the Pope did not touch base with Luis Guerrero. This is a small omission, but it might have helped explain what the Catholic Church perceives as a decline in believers in the Americas. PNS commentator Sam Quinones is a Mexico City-based writer.

SAN QUINTIN, MEXICO -- Last summer, I met a man named Luis Guerrero -- a man the Pope would have done well to speak with during his recent visit here.

Guerrero lives in the valley of San Quintin, a bustling Baja California agricultural valley four hours south of Tijuana. A farmworker, he speaks halting Spanish in a heavy Indian accent.

Guerrero told me the story of his conversion to Protestantism from the traditional Catholicism of his pueblo in Oaxaca.

In Guerrero's home pueblo, Catholicism was the only religion. No one read the Bible, or even owned one -- the local priest interpreted it for them.

Religion and tradition were tightly bound together. Every year a few people in the village were selected to pay for the annual three-day party honoring the local patron saint. Guerrero's turn came in 1972, and he had to borrow the equivalent of two years' wages to buy candles, alcohol, food, and fireworks.

He then left for a year to pick tomatoes in northern Mexico to pay off the loan, and eventually settled his family in San Quintin. And there, away from the cloistered tradition of his pueblo, he experienced an awakening. He bought his first book ever -- a Bible.

"I began reading it and I began to awake my mind," he says. "That's where I understood that the priests hide part of the word of God. The word of God prohibits images, sculptures. I know how to read a little. I read the Ten Commandments. Exodus, chapter 20. Isaias 44:9, which talks about idolatry."

Thirsting for more, he bought his second book -- a copy of the Mexican Constitution. "In our pueblos in Oaxaca, we didn't know the earthly law, or how to defend ourselves (legally). Also we didn't know spiritual law. So I searched on my own to discover what constitutional law said. I searched on my own to discover what the Bible said."

Today, he and his family are members of the Pentecostal Apostolic Assembly of Faith in Christ Jesus. His son Vicente, 21, is a pastor's helper, and occasionally preaches. And the family has begun to advance economically -- Vicente is also a computer technician, something impossible to conceive of back in Oaxaca.

Luis Guerrero's awakening and journey into the world is Mexico's journey as well, and I believe it holds a great message for the Catholic Church today. Protestant groups in Mexico claim 20 million believers, while the Church estimates 90 million Catholics. Since Mexico only has 100 million people, someone's off -- but it is certain that the Catholic Church is under serious attack. Its losses are especially acute among poor people, like Luis Guerrero.

Mexicans have as many reasons for changing religions or losing faith as any one else. In part, this simply reflects the fact that ours is a secular age dominated by technological advance, Hollywood cynicism, and free-market capitalism.

But beyond that, the crisis facing the Catholic Church here is part of a general crisis of credibility facing most Mexican institutions.

Mexicans have lived with monopoly in every important part of life for most of this century. The Institutional Revolutionary Party (PRI) has ruled for 70 years. High tariffs and stiff import rules protected Mexican industry, there was only one television network, official unions controlled their members' work lives.

So, too, the Mexican Catholic Church had a religious monopoly.

The Church likes to blame Protestant advances on heavy financing from U.S. churches, and there is something to that. But more important the church now has to compete -- Mexico has entered the world and is more skeptical and demanding because of it. Today Mexicans bear a profound mistrust toward those institutions that once monopolized their lives.

Protestant groups have simply tried harder to meet the needs of believers in a country that has borne more than 20 years of economic crisis.

For Mexicans, real choice has been a revelation. President Carlos Salinas opened the borders to foreign-made goods in the early 1990s and unleashed awesome pent-up demand for quality shampoos, bras, stereos and televisions. So the Church must gird itself to outside competition in the world of ideas. One response has been to provide stickers that proclaim "This Home is Catholic" and warn representatives of rival faiths not to even knock.

Mexico will remain Catholic, and the Church will continue to be a warm hearth of comfort for millions. But the trend toward religious pluralism will not be arrested and the Church like other Mexican institutions will have to do more than issue stickers if it is to remain relevant to a people increasingly open to new possibilities.