the worse it becomes in Europe, the more WASPS and Catholics will flee to America, thus disrupting the trends that rabblerousers love to predict.Or vice versa ... mutatis mutandus ... ceteris paribus ... et cetera ...
What makes you so sure they'd flee here sooner than some people here would flee there?
imo, there are only two places left on earth where advanced European-styled civilization can be maintained and nurtured through the next world war: Australia/NewZealand and USA/Canada. The weather is better in the States, we have more natural resources, a larger habitable land mass, only two neighboring countries of note, no caste-systems preventing employment, a stronger social and moral network, a more stable government and a higher percentage of population survivabiliity of any wmd attacks. We also have the world's best overwhelming military response capability, and can be relatively self-sufficient amongst our neighbors if need-be.
America is the most logical choice for a European exodus, and, I believe, is destined for that exact purpose.