Here are excerpts from the U.S. Supreme Court’s opinions in Elk Grove Unified School District v. Newdow, regarding the inclusion of the words “under God” in the Pledge of Allegiance.
From the majority opinion by Justice Stevens, joined by Justices Kennedy, Souter, Ginsburg, and Breyer:
In every federal case, the party bringing the suit must establish standing to prosecute the action. ...
One of the principal areas in which this court has customarily declined to intervene is the realm of domestic relations. ...
This case concerns not merely [Michael A.] Newdow’s interest in inculcating his child with his views on religion, but also the rights of the child’s mother as a parent generally and under the Superior Court orders specifically. And most important, it implicates the interests of a young child who finds herself at the center of a highly public debate over her custody, the propriety of a widespread national ritual, and the meaning of our Constitution. ...
In our view, it is improper for the federal courts to entertain a claim by a plaintiff whose standing to sue is founded on family law rights that are in dispute when prosecution of the lawsuit may have an adverse effect on the person who is the source of the plaintiff’s claimed standing. When hard questions of domestic relations are sure to affect the outcome, the prudent course is for the federal court to stay its hand rather than reach out to resolve a weighty question of federal constitutional law. There is a vast difference between Newdow’s right to communicate with his child—which both California law and the First Amendment recognize—and his claimed right to shield his daughter from influences to which she is exposed in school despite the terms of the custody order. ...
From the opinion by Chief Justice Rehnquist:
... 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]. Instead, it is a declaration of belief in allegiance and loyalty to the United States flag and the republic that it represents. ... 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.
From the opinion by Justice O’Connor:
...It is unsurprising that a nation founded by religious refugees and dedicated to religious freedom should find references to divinity in its symbols, songs, mottoes, and oaths. ...
The phrase “under God,” conceived and added at a time when our national religious diversity was neither as robust nor as well recognized as it is now, represents a tolerable attempt to acknowledge religion and to invoke its solemnizing power without favoring any individual religious sect or belief system. ...
From the opinion by Justice Thomas:
... Through the pledge policy, the state has not created or maintained any religious establishment, and neither has it granted government authority to an existing religion. The pledge policy does not expose anyone to the legal coercion associated with an established religion. Further, no other free-exercise rights are at issue. It follows that religious liberty rights are not in question and that the pledge policy fully comports with the Constitution.