On Tuesday, a U.S. Supreme Court decision barred the execution of criminals who had committed crimes before the age of 18, overturning a 1989 High Court decision.

The decision, based on a 1993 Missouri case, commutes the death sentences of 72 criminals in 12 states.

The majority based its decision on three arguments, the third of which focused on international opposition to the juvenile death penalty. Justice Anthony M. Kennedy said in the majority opinion that, although “the court was not bound by foreign developments, it is proper that we acknowledge the overwhelming weight of international opinion” for its “respected and significant confirmation for our own conclusions.”

The Court’s 5-4 split on the case reflects our own ambivalence.

We agree with the Court’s decision, but have reservations about using international opinions and policies to interpret the Constitution.

In the case of the Eighth Amendment, which bars “cruel and unusual” punishment, contrasting U.S. policy with the rest of the world to determine what is “unusual” does seem appropriate.

In the opinion, Kennedy noted that “only seven countries outside the United States have executed people for crimes they committed as juveniles, and all seven — Iran, Pakistan, Saudi Arabia, Yemen, Nigeria, China and Congo — have disavowed the practice.”

That the United States is the last country in the world to disown the practice seems irrefutable proof that it is unusual.

We can think of few other instances, however, when such a U.S. law/international opinion contrast is relevant.

Would we be willing to follow western Europe’s lead and abolish capital punishment altogether? Would we follow Africa and the Muslim world’s laws and customs concerning women in society? Would we follow China (the world’s most populous country) in governance of the family or the media?

We should hope not.

In a scathing dissent, Justice Antonin Scalia disagreed with using international opinion as a basis for a decision, writing that the majority opinion rendered “the views of our own citizens are essentially irrelevant,” and that the court gave “center stage” to the “so-called international community.”

Although we don’t believe this particular case left U.S. citizens’ views irrelevant, it is apparent to us that dependence on international opinion could lead down that path.

The Supreme Court must be cautious about looking outside the United States to interpret the Constitution. Although justifiable in this case, such capitulation to international opinion could be a slippery slope away from the ideals and principles that make this country what it is.