I am pretty convinced that Roberto Blancarte's prediction of the demise of Catholicism in Mexico is a bit on the "jumping the gun" side, considering the incredibly strong youth movement in the country. As David Espinosa demonstrated with his work on Jesuit education and Mexico's youth, the construction of powerful networks are built that later reinforce Catholic power. Add that to Roderic Camp's research on the strength of Mexican camarillas (political families), and I am pretty sure that the enthusiasm of Mexico's Catholic youth will work to maintain Catholic power in the country.
This is not a simple game of numbers, as the Charismatic movement within Catholicism successfully lures back the converts as well as maintains the attention of the youth. Even the use of technology is an effective arrow in the quiver of the Roman Catholic Church and their youth. For example, last summer I was doing research in Tepalcingo, Morelos - as remote a municipio as it gets in Morelos. What kept the youth organized? Facebook. Conversion to Protestantism (and to no religion at all) may be growing in Mexico, but the idea that Catholicism will dip below a majority in the country is unthinkable.
Check out this clip of youth who describe themselves as the "escuadron hormiga of the army of Maria" (the ant squadron from Maria's Army) from the media operation out of Guadalajara Radio Maria.
The ant reference is interesting. Those in tune with modern Mexican politics should immediately catch the use of hormiga as similar to that being used by Subcomandante Marcos and the EZLN: the "small" folks working together can accomplish incredible tasks - so watch out. Considering the grassroots politics mobilizing across ever since 1985 and the Mexico City earthquake, I certainly think Mexico has something to teach us about the power of the ants - from every political and religious persuasion.