@judgedread This depends on what you consider "Christianity".

Prot tards who feel their feelings (in lieu of proper rational faith) and reject 5 out of 7 Sacraments are naturally getting weaker.

The Roman Mass according to the last Church Calendar (1962) and Eastern Orthodox Liturgy, both accepted by Rome (though the East-West unity hasn't yet occurred) are both growing in the US. Under the Roman rite Novus Ordo is bleeding because people are more aware now than ever that it is almost as watered down as vapid Prot heresy.

Look into SSPX and FSSP parishes, look into the growth of the Tridentine Mass (esp. since Pope Benedict XVI's Summorum Pontificum), look into the explosion of Eastern Orthodoxy. These things are exploding with growth. You need to arrive an hour early for Low Mass to get a seat in the overflow rooms. They cannot build fast enough to house new parishioners.

These are generally more resilient people having a dozen kids apiece, marrying within their parish, protecting their daughters and raising strong sons. Homeschoolers, homesteaders, one family interdependent with nearly every other family in the parish, every one of these places provides insulation against the miasma of American rot and degeneracy. Very White, as well, though the swarthier varieties can't be excluded entirely (and for the Church really shouldn't be - that's primarily a state function to be supported by the Church, iirc). Regardless, it appeals primarily to Whites naturally.

True Doctrine, real strict adherence to Christian virtue, is on the rise. (((They))) specifically fear the proper Apostolic Succession, too, as they're sitting plainclothes feds in Tridentine Masses, and presumably Orthodox Liturgy as well.

Somehow they're not bothered at all by Pastor Jim's Bible-Church™.

@thefinn