Here’s the Court’s ruling on the pledge of allegiance case, which reverses the 9th Circuit Court of Appeals ruling for Newdow’s lack of standing. From the syllabus:

Because California law deprives Newdow of the right to sue as next friend, he lacks prudential standing to challenge the school district’s policy in federal court. The standing requirement derives from the constitutional and prudential limits to the powers of an unelected, unrepresentative judiciary.

Although Rehnquist, O’Connor, and Thomas agreed with Stevens’s unanimous decision that the lower court ruling be reversed, they did not agree that Newdow lacked standing. Hence, in their separate concurrences they argued that the case should have been heard on the merits and gave their respective reasons for what the Court should have held in the case. Rehnquist’s concurrence, joined by O’Connor and Thomas insofar as it argued for a decision on the case’s merits (Scalia recused himself), argued:

I do not believe that the phrase “under God” in the Pledge converts its recital into a “religious exercise” of the sort described in Lee [v. Weisman (1992), Justice Kennedy’s opinion for the court]. Instead, it is a declaration of belief in allegiance and loyalty to the United States flag and the Republic that it represents. The phrase “under God” is in no sense a prayer, nor an endorsement of any religion, but a simple recognition of the fact noted in H. R. Rep. No. 1693, at 2: “From the time of our earliest history our peoples and our institutions have reflected the traditional concept that our Nation was founded on a fundamental belief in God.” Reciting the Pledge, or listening to others recite it, is a patriotic exercise, not a religious one; participants promise fidelity to our flag and our Nation, not to any particular God, faith, or church.

O’Connor considered the pledge an instance of "ceremonial deism." Due to its history and ubiquity, the absence of worship or prayer or reference to a particular religion, and minimal religious content, it does not violate the establishment clause of the First Amendment.

Thomas argued that

as a matter of our precedent, the Pledge policy is unconstitutional. I believe, however, that Lee [v. Weisman] was wrongly decided. Lee depended on a notion of “coercion” that, as I discuss below, has no basis in law or reason. The kind of coercion implicated by the Religion Clauses is that accomplished “by force of law and threat of penalty.” 505 U.S., at 640 (Scalia, J., dissenting); see id., at 640—645. Peer pressure, unpleasant as it may be, is not coercion.

But Thomas went on to argue that rejecting the 1992 Lee precedent was not enough to decide this case, for school attendance is mandatory in California. He continued, "Because what is at issue is a state action, the question becomes whether the Pledge policy implicates a religious liberty right protected by the Fourteenth Amendment." Accepting that the Free Exercise clause applies to the states through the 14th Amendment because it "clearly protects an individual right," Thomas does not accept that the Establishment Clause applies in the same way. Its history shows that it is "a federalism provision intended to prevent Congress from interfering with state establishments," which makes incorporating the establishment clause nonsensical. "Quite simply," Thomas concluded, "the Establishment Clause is best understood as a federalism provision–-it protects state establishments from federal interference but does not protect any individual right."

So, three justices have taken the opportunity of the Court’s refusal to rule explicitly on the constitutionality of the pledge of allegiance to stake out their respective lines of reasoning for a future case involving an alleged establishment of religion. Justice Kennedy rests easy for the time being.