The Pope explained this today when analyzing the conditions that prompt thousands of Mexicans to cross the border into the United States.
The Holy Father addressed the topic during the ceremony at which he received the credentials of the new Mexican ambassador to the Holy See, Javier Moctezuma Barragán.
"To the uncertainty of those who leave in search of better conditions," the Pope said, "is added the problem of cultural uprootedness and the painful dispersion or distancing of the family, without forgetting the disastrous consequences of so many cases of clandestinity."
In the last three years, 1.17 million Mexicans have emigrated to the United States, according to studies provided by Francisco Alba, a researcher at the Mexican College, and others. Every day, more than 1,000 Mexicans successfully cross the border with the intention of not returning to their country, data show.
Regarding immigration controls, the Pope said: "The Church reminds all that the measures developed in host countries must be accompanied by determined attention to the country of origin, where emigration is managed."
He called for the "detecting and remedying, above all, of the causes that make so many citizens feel obliged to leave their land."
Moreover, "Mexicans residing abroad must not feel forgotten by the authorities of their country, who are called to facilitate assistance and services that will help them maintain contact with their land and their roots," the Pope added.
In this context, John Paul II encouraged "meetings between bishops of border dioceses of Mexico and the United States" to seek "joint measures to improve the situation of the emigrant population."
He added: "Parishes and other Catholic institutions are the principal points of reference and identity that they find abroad."