--- - |2 Abstract Scholars over the past several decades have noted the resilience of religion in the United States (Chaves 2011; Gorski and Altınordu 2008; Hadden 1987:601–02; Presser and Chaves 2007), but many recognize that the youngest U.S. cohorts are significantly lower on several religious characteristics than older cohorts (Hout and Fischer 2014; Putnam and Campbell 2012; Voas and Chaves 2016). Scholars have proposed several explanations for this trend, disagreeing about whether it is the result of a particular cultural moment or an ongoing process leading to even greater religious decline. Voas (2009) proposed one such explanation. He used European data to show that the proportion of nonreligious people in each cohort only became significant when previous cohorts reached a critical mass of moderately religious people. Voas’s model is novel and promising but has neither been examined statistically nor applied to U.S. data, which I take up here. I find that, surprisingly, the United States fits closely on the same trajectory of religious decline as European countries, suggesting a shared demographic process as opposed to idiosyncratic change. I conclude by discussing how these findings inform theories of self‐reinforcing religious decline and cross‐national patterns of religiosity. - 'Journal for the Scientific Study of Religion, EarlyView. '