How does religious nationalism arise? Poland and the Philippines represent two striking examples of religious and national identities becoming practically coterminous. Yet these two Catholic nations traveled different historical paths towards a tight fusion of religion and nation. In Poland, the church defended the nation in dramatic struggles against a strong and secularizing state. This fused religious and national identities, endowing the church with unrivaled moral authority. In the Philippines, the church historically substituted for a much weaker state by serving the nation both symbolically and materially in ways that secular authorities never matched. Our comparative-historical analysis thus demonstrates that similar religious nationalisms can arise via distinct political pathways: through struggle against an interventionist state and by substituting for an ineffective state.