American civil religion's most visible symbols, "In God We Trust" on currency and "under God" in the Pledge, have generated a recurring line of constitutional litigation that shows courts grappling directly with the definitional problem the main entry raises: whether civil religion is genuinely religious or merely a secular formality invoking religious language without content.
"Under God" was added to the Pledge by Congress in 1954, during the Cold War, explicitly to distinguish the United States from atheistic communism, an origin critics argue undercuts any claim that the phrase is a neutral, non-religious formality. Legal challenges culminated in Elk Grove Unified School District v. Newdow (2004), where the Supreme Court avoided ruling on the merits by finding the plaintiff lacked standing to sue on his daughter's behalf, leaving the Establishment Clause question unresolved, though lower courts have generally upheld the phrase by invoking ceremonial deism, the idea that certain religious references have, through long repetition, lost their religious significance and become secular ritual formulas, a doctrine some justices, including Sandra Day O'Connor, endorsed while others expressed considerable skepticism.
The ceremonial deism doctrine is, in effect, a judicial attempt to resolve the ambiguity the main entry describes as central to civil religion generally. Critics on both sides have pointed out the same awkwardness: if the phrase has really become religiously meaningless through repetition, it is unclear why removing it should offend anyone, and if removing it would offend people, that is itself evidence it has not become meaningless, an argument the courts have never fully resolved and have mostly avoided rather than answered.