The view of America as a Christian nation, founded on Christian principles is quite controversial, to say the least, and reflects some unsupportable revisionist history (exemplified by the Texas Board of Education textbook standards that delete Thomas Jefferson from a list of influential political thinkers). But putting that controversy aside, or even conceding for the sake of argument the presumptive Christianity of a few Founders, the hard question remains: what difference should it make to judges interpreting the Constitution today? Are historical customs and ideals reference points, or mandates?
Judge Crabb unequivocally rejected the proposition that "religious conduct that would otherwise violate the establishment clause may be upheld for the sole reason that the practice has a long history...If one were to read the establishment clause as permitting any practice in existence around the time of the framers, this would likely mean that the government would be free to discriminate against all non-Christians." So, while "early Congress's political actions" are "relevant," she observes (quoting Justice Souter,) they are not "determinative ... of constitutional meaning." This view is countered by the originalist approach to constitutional jurisprudence, articulated most famously by Justice Scalia and shared by ADF's Joel Oster. In his view, the First Amendment's ban on established religion was "only intended to prohibit a state church," not official religious exercises, like prayer or Ten Commandment displays.
Oster and other advocates of official religiosity (and official Christianity in particular) aim to reverse the "last fifty years or so" of establishment clause rulings, which they regard as "inconsistent" with the Founder's intent. In this view, the Supreme Court's 1962 decision invalidating the New York State school prayer marked the beginning of a radical departure from the path of constitutional righteousness. (I recited this prayer resentfully every day, throughout elementary school, although I can't say I was harmed, much less indoctrinated by it (which didn't make it right). Instead, compulsory recitation of the prayer, followed by the Pledge of Allegiance, only increased my sense of alienation from religion and nurtured a healthy distrust of nationalism and other collectivisms.)
Official school prayers seem unlikely to be reinstated, thanks partly to the difficulty of fashioning one prayer that satisfies all prayerful and politically influential religionists. But the Supreme Court is gradually adopting a more permissive view of government sponsored religious activities. It's progress, or regress, is fitful -- in 2005, the Court ruled for and against two respective official Ten Commandment displays -- but the trend seems clear. Just this week, in Salazar v Buono, the Court upheld a controversial congressional land transfer designed to allow a large cross to remain on display in the Mojave National Preserve. In 2007, in Hein v Freedom from Religion Foundation, the Court struck down FFRF's challenge to executive branch expenditures in support of the Bush Administration's "faith-based" initiatives.