"Comprehensive Immigration Reform" A Power Grab?

Both Presidential candidates favor "Comprehensive Immigration", which most of us know is an euphenism for "Amnesty", the legalizing of illegal aliens. Arguments against such "reform" not heard so far is how such legalization will effect political and economic power in the U.S.; namely that allowing 20 million or more Catholics into this country will "stack the deck" in favor of the Vatican. No wonder the Catholic clergy are so vocal in favor of amnesty. Would they be so vocal if the majority of illegal aliens were Buddists or Muslims? I don't think so.
Allowing that many new residents in will further contribute to Labor's problems, by lowering wages and losing jobs, which benefits Corporations but erodes the Middle Class. The most immediate and serious of impacts a "hit" Social Security will sustain with that many new enrollees being added to the rolls. It will bankrupt Medicare as well.
If only there were as zealous and powerful advocates for the average American as there is for illegal aliens.
So far our Presidential candidates have run away from the issue; McCain notably shying away from questions posed to him during his Town Hall meetings. They can run but not hide.