Answerable to virtually no one, the ICC was created by the 1998 United Nations’s Rome Statute to prosecute war and other “serious” crimes. It has yet to convict anyone. President Clinton signed the Rome treaty but didn’t submit it for Senate ratification and urged his successor not to, citing the absence of protections against prosecutions of America’s servicemen. In 2002, the Bush Administration informed the U.N. that the U.S. felt in no way legally bound by Mr. Clinton’s signature.

The Obama Administration is taking steps to re-engage with the ICC. For the first time, the U.S. showed up last November at a meeting of ICC signatory countries. The American delegation included the State Department’s top lawyer, Harold Koh, a vocal ICC proponent. Next month, U.S. observers will go to a special “review conference” in Uganda that will consider changes to the Rome Statute.

Some U.S. officials, such as Mr. Koh, support what they call “pragmatic cooperation” with the ICC—for example, helping it with investigations and sitting in on court bodies.

Proponents argue that this would give the U.S. a voice on decisions that affect its interests, such as helping the ICC define the “crime of aggression.” U.S. officials were stunned that a recent draft defining aggression was so wide-reaching that NATO would have been criminally liable in the 1999 Kosovo war. The court’s powers aren’t retroactive, but proponents ask why shouldn’t the U.S. be in the room to stop this nonsense in the future?

Color us skeptical. The ICC’s indictments have so far targeted nasty characters in Africa, but the court has always resisted outside oversight, especially from the U.S. What’s more, no amount of reform of the founding treaty will change the ICC’s inherent flaw. The ICC is a child of the doctrine of “universal jurisdiction,” which holds that courts can adjudicate crimes committed anywhere in the world. Politically ambitious prosecutors in Belgium, Britain and Spain have invoked “universality” to go after Ariel Sharon and Donald Rumsfeld, among others, for alleged war crimes.

Eight years ago, Mr. Koh hailed the court’s creation as “an international Marbury versus Madison moment,” referring to the 1803 Supreme Court decision that gave a fledgling court authority over other branches of government. By this logic, the world court should have similar power over America’s democratic decisions and global leadership. No thanks.

From the Balkans to East Timor to the Mideast, these pages have welcomed international action to stop atrocities. In select cases, such as the U.N. war crimes tribunal for the former Yugoslavia, we’ve backed ad hoc courts with a narrow mandate, limited life and proven commitment to fairness. The ICC meets none of those standards.

Moral grand-standing via indictments also isn’t the same as doing something about crimes against humanity. The indictment of Sudan’s butcher of Darfur, President Omar Hassan al-Bashir, made him harder to dislodge, and absent serious intervention, it has probably prolonged the suffering there.

The ICC is spending $125 million on a six-building campus near the Hague. The U.S. may not be able to stop the latest U.N.-style bureaucracy from rising, but that’s no reason to invest American credibility and resources in this project.