Congressional voting patterns on immigration policy differ strikingly according to the religious affiliation of the elected official. Jews and Catholics are the strongest immigration enthusiasts. It's an update of the old saying about the Mafia: Jews provide the moxie (money/media support), Italians (Catholics) the muscle (votes). In contrast, Presbyterians, as a group, are the strongest advocates of immigration restriction.
Episcopalians, with about as many federal legislators as Jews, present a paradox. In the U.S. Senate, they are decidedly pro-immigration. But in the House, they are decidedly pro-restriction (at least relative to the generally disgraceful standards of federal politicians). This may reflect the fact that it takes a lot more money to run a Senate race, so there is a lot more need to sell out to win. This is part of why, as a progressive, I personally think we need publicly funded elections and a lifetime ban on Senators taking money from any source other than their Senate salary/pension—even if it means paying these folks as well as they do in Singapore…and I would treat infractions even more harshly than they do there.
But also the pool of Episcopalian members tends to reflect all the people who were ever confirmed as Episcopalians, many of whom have never been active in that denomination as adults and may even have other religious affiliations—as, apparently, John McCain now does.