The words “God save the United States and this Honorable Court!” are not mere “ceremonial deism.” This phrase was made up by Eugene Rostow in 1962 when he was dean of Yale Law School, and used calculatingly and wrongly by Justice Brennan in Lynch v. Donnelly (1984) to claim that these references to God “have lost through rote repetition any significant religious content.”True, but two points. One is the understanding of "Deism" being offered here is that of the impersonal God of "strict Deism." Arguably there are other viable definitions of the term. However to many very learned folks in today's scholarly discourse (such as Nussbaum and Forte) that's what the term has come to mean.
As Professor Martha Nussbaum at the University of Chicago Law School noted, “‘Ceremonial Deism’ is an odd name for a ritual affirmation that a Deist would be very reluctant to endorse, since Deists think of God as a rational causal principle but not as a personal judge and father.”
Second, if you look at the utterances from the Founding era that Forte offers to support the claim, they are all, we could say, generically monotheistic: James Madison's "Governor of the Universe"; Thomas Jefferson's liberty securing, gifting "God" of justice; the "Creator" of the Declaration of Independence who endowed men with "unalienable rights"; and George Washington's "Almighty Being who rules over the Universe."
None of these is necessarily the Triune God of orthodox Christianity. If you read Forte's article in detail, you see he attempts to answer a question posed by Justice Kagan that basically asked (my words, not hers) "what if this Court endorsed Christianity?" It doesn't but it does endorse generic God belief.
"Ceremonial Deism" is a word off putting to many of those who like terms like "so help me God" and "God save ... this Honorable Court."
What about "generic monotheism"?