Objective The relationship between beliefs about the cause of homosexuality, political and religious ideology, and attitudes toward same‐sex unions in the United States is unclear. This study aims to examine the mediating influence and socially embedded nature of attribution beliefs at a time when attitudes toward same‐sex unions are undergoing substantial changes in the American public. Method This study employs simultaneous equation path models and a recent national, random sample of American adults (Baylor Religion Survey 2010) to test each hypothesis. Results Results reveal that constructed opinions about the origin and controllability of homosexuality significantly influence support for same‐sex unions. However, these opinions are socially embedded, especially within particular political and religious ideologies. Conclusion These findings highlight that while widespread changes in beliefs about the cause of homosexuality may presage shifts in support for same‐sex unions, many will be able to resist those shifts toward support, possibly leading to their further marginalization within society.