The spectacular growth of Protestantism in countries like Brazil, Guatemala, Peru and, to a lesser extent, Mexico, is one of the ways in which ordinary Latin Americans have revolted against centralized power. Unlike the Catholic Church, which has always been associated with the status quo, the various evangelical cults that have gained strength among the poor speak to a more flexible, decentralized and less hierarchic form of religion. More importantly, the Catholic Church is perceived as being attached to the elites. Since only one quarter of respondents said citizens are equal before the law in their countries, it is hardly surprising that an institution perceived as part and parcel of a discriminatory system is losing support to religious groups that have penetrated the shantytowns with a message of spiritual revolt against the status quo, emphasizing self-help and social cooperation as substitutes for state action.
He finds the link in the connection between both the U.S. and Catholicism with the status quo:
Among many Latin Americans, there is the perception that the U.S. is too closely allied with political and business elite groups. These are the very groups that ordinary Latin American citizens have been revolting against for decades, by moving to a different church, by supporting “outsiders” in various Presidential elections against traditional parties or by creating substitutes for state services at the grassroots level. Among some Latin Americans, the U.S. is perceived as another pillar—like the Catholic Church, traditional parties, or the military—of the prevailing system.
There is surely some irony here, since a major reason for the boom in Protestantism in Latin America is the flood of American Protestant missionaries into those countries. (On an anecdotal level, every flight I have taken to Guatemala in the past 5 years has been packed with missionary groups, identifiable by their matching t-shirts.) A further irony is that American anti-Catholicism has only recently receded to any significant degree.
There are a couple of points I wish Vargas Llosa had addressed, however:
1) He argues that one reason for the US identification with the status quo is that ordinary Latin Americans don't have contact with ordinary Americans, but instead see only diplomats, etc. on TV. But Protestants would be more likely to have contact with ordinary Americans through missionaries.
2) Catholicism provides a fairly dense social networks in many Latin American countries through various organizations such as local groups that care for saints. Protestant churches tend to have a much flatter organization, perhaps for theological reasons and perhaps because they are newer. Is there a connection between being divorced from the social networks and politics?
3) the major phenomenon of the recent years has been the rise of the "indigenous" movements, fueled by Cuban and Venezualan support, in countries like Bolivia. These groups are neither Protestant nor Catholic but, from what I can tell from media reports, harken back to animistic beliefs. An alternative plausible explanation for the changes in perception of the US could be linked to these groups rather than Protestantism. I'm not sure there is sufficient data to disentangle the two competing explanations.