The U.S. Supreme Court's decision last week to preserve the due process rights of inmates at the Guantanamo Bay naval base was encouraging on several levels.

First, it upheld the fundamental principle of checks and balances. In this case the judicial branch — for the third time in four years — rebuked the Bush administration for denying Guantanamo Bay inmates the right to challenge their lengthy imprisonment through the civilian courts.

And the ruling rightly sets a new and more credible course in how detainees are treated.

That change was long overdue. In 2004 the Supreme Court ruled that detainees had the right to challenge their imprisonment in a U.S. court under habeas corpus.

But a compliant Congress, under pressure from the administration, quickly passed a law to strip the federal courts of that jurisdiction.

Today, more than 250 detainees are housed at Guantanamo Bay; some have been held more than six years without being charged.

Above all, the court's decision reinforces a fundamental right: the right to challenge the legality of imprisonment through the courts. It does not set a single terrorist or suspected terrorist free.

What it does do is press the government to prove its cases and file the appropriate charges. And the cases of Jose Padilla and Zacarias Moussaoui — both tried and convicted on terrorist charges in the civilian courts — show the system does work.

The Supreme Court got it right. Requiring that the inmates be treated fairly under the rule of law enhances our credibility and our moral authority — both of which are sorely needed as the U.S. sets about refining its policies in the war on terrorism.