Religiosity has been declining in 33 of the 49 countries representing 60% of the world's population, since 2007. Factors such as increased wealth and declining birth rates are major factors worldwide.

But the decline is steepest in the US. Politicization and weaponization of religion in the US is undoubtedly the key factor here. Republicants saw religious zealots as another voting bloc, and the believers in return saw the party as their tool to smite the godless. The party used them, they used the party. The party got the better part of the deal.