Regarding Holy Trinity, you're noting dicta that has no legal basis. It's easy to find analysis putting that statement into appropriate context: such as:
Whether or not America was a Christian Nation was not even at issue in Holy Trinity. The actual dispute or controversy the Court had to decide had nothing at all to do with religion. The parties in Holy Trinity did not question whether the Immigration Act's purpose was "for or against religion" generally or specifically. So when Brewer begins his religious history lesson with, "no purpose of action against religion can be imputed to any legislation, state or national, because this is a religious people," he refers to no particular statute, no particular actor. He has moved outside the actual facts of this case and the statute at issue to address the vague application of general principles to law in general. His statements, therefore, create no rule of law, and provide no useful precedent for future legal disputes. As any basic Legal Research textbook will confirm, the legal researcher will not find precedent in such language, but must look for "the [legal] rules stated by courts [which] are tied to specific fact situations" (The Fundamentals of Legal Research, 1994, Jacobstein et al, page 6).From: http://www.philosofiles.com/big/atheistground/peters-churchstatereply.shtmlBrewer's comments about religion are not tied to any of the facts as presented in Holy Trinity. The Holy Trinity Church did not allege in the facts of its case that the purpose of the Act was to discriminate against a particular religion nor that it was designed to prevent the members of their church from the free exercise of their religion. Since none of the facts suggested that the clergyman was being kept out of the country for the purpose of discriminating against religion or prohibiting religious exercise, the dictum by Brewer addresses no controversy and crafts no rule of law to be applied to other cases as precedent.
Holy Trinity's legacy includes a number of Supreme Court cases which cite the opinion as support for either statutory construction based on legislative intent or the use of immigration policy to exclude or include immigrants. Only on three occasions does the Holy Trinity christian nation dictum make an appearance in a Supreme Court case.
In the 1931 case of U.S. v. Macintosh, an ordained baptist minister was denied naturalization because he was unwilling to take an oath to bear arms in defense of the country unless he believed the war necessitating the defense to be morally justified. As in Holy Trinity, the legal rule established by this case had nothing to do with the christian nation quote. Instead, the applicant was denied citizenship based on a reading of the naturalization statute which required the oath.
However, in Macintosh dictum, Justice Sutherland writes, "We are a Christian people, according to one another the equal right of religious freedom, and acknowledging with reverence the duty of obedience to the will of God." Sutherland then states that as a nation we must assume that obedience to our laws is "not inconsistent with the will of God;" therefore, a foreign-born person refusing to follow the naturalization statute to the letter would be denied citizenship.
There are a couple interesting notes about Macintosh. First, in Holy Trinity, Brewer uses the phrase "we are a christian nation" to allow a foreign-born minister access to this country. In Macintosh, it is used to keep a foreign-born ordained minister out. Second, a different result would most likely have occurred had this case arisen after World War II when the court overturned the Macintosh line of cases (Girouard, 1946).
The other two cases which cite Holy Trinity's christian nation dictum are Marsh v. Chambers (1982), and Lynch v. Donnelly (1983). Brennan writes dissents in both cases and uses the Brewer verbiage to criticize the majority's use of history to support legislative prayer and a government sponsored creche. In the creche case, (Lynch), Brennan writes, "By insisting that such a distinctively sectarian message is merely an unobjectionable part of our 'religious heritage,' the Court takes a long step backwards to the days when Justice Brewer could arrogantly declare for the Court that 'this is a Christian nation.' Those days, I had thought, were forever put behind us ...."
The analysis one would expect from a philosophy/atheism web site.