IT IS UNDERSTANDABLE that the government of the United States has difficulty protecting the rights of its citizens in faraway places like Iran and Afganistan. They are beyond American control -- and occasionally beyond their own. It is not so easy to understand why the same government has difficulty protecting the constitutional rights of certain groups of citizens in places like Maryland and Montana. But it does -- if those citizens happen to be inmates of state institutions. Even if the Department of Justice knows those inmates are being systematically abused, it can't do anything about it.

Legislation to change that situation has been fully debated on Capitol Hill in the last two years. It would give the Department of Justice authority to file lawsuits in federal court on behalf of such inmates. Once the cases are in the courts, judges can enter whatever orders are needed to protect the rights of prisoners in jails or patients in mental hospitals or juveniles in detention facilities. As the law stands now, those cases can reach court only if the inmates bring the lawsuits themselves. The problems of that situation are obvious; mental patients may not know, for example, that they are being deprived of their rights and, even if they do know it, their ability to initate a lawsuit is limited.

The House of Representatives passed this legislation overwhelmingly last summer, but it died in the Senate after it was vigorously opposed by the National Association of State Attorneys General. A majority of its members regard the bill as an attack on states rights. They are right in the sense that the federal government should not have to compel state institutions to do what the Constitution requires them to do. But the evidence is overwhelming that some of those institutions do not give their inmates the rights to which they are entitled -- and will not do so unless a federal court forces them to change their ways.

The legislation has been reintroduced this winter and is now pending before the Senate Judiciary Committee. It ought to be speeded on its way to passage. The federal government has enough problems protecting the rights of citizens abroad without being denied -- on so small a technicality -- the ability to protect them at home.