Growing populations of Muslim immigrants in Europe and the U.S. have already been labeled causes of terrorism. And if many U.S. pundits claim Christians are a persecuted group while maintaining a majority of 78 percent, it’s difficult to imagine how shrill the militarized language of attack will be when Christians are holding on by a two-thirds-of-the-population thread. The feeling that Christians are already under attack and shortly will be outnumbered in a hypothetical Holy War is what is at issue here.

If this should really be understood as a kind of spiritual arms race, then Christianity is “losing” because Christians, to quote Pope Francis, no longer feel the need to “breed like rabbits.” Christianity is still on the rise, but its growth is slowed by low fertility rates, especially in wealthier countries.

To the environmentally minded, this is probably not a bad thing. The earth can’t sustain a population explosion of consumption-heavy Westerners. Who cares if Christians match Muslims in numbers if there isn’t a planet to inhabit?