THE SENATE Foreign Relations Committee recently heard some horror stories that didn't originate in Managua or Beirut. Witnesses testified about crimes committed against American citizens in this country by foreigners with diplomatic immunity. The senators were told of the officials in the Afghan U.N. Mission who ran down a New York City girl because they wanted her parking space. They heard testimony about a series of rapes attributed to the son of an attache' at the Ghanaian mission, an assault by the Mexican ambassador to the U.N. and a shooting by the son of the Brazilian ambassador in this city. None of those charged was prosecuted criminally because each had diplomatic immunity. It makes the blood boil. And, reflecting this, Sen. Jesse Helms has proposed legislation that would do away with diplomatic immunity for all but a handful of senior diplomats. Families and administrative and technical personnel at embassies would be subject to prosecution.

Satisfying as the idea sounds -- and no one can deny a powerful desire to do something about these immunized outrages -- the State Department has entered strong and plausible objections. Diplomatic immunity, as Protocol Chief Selwa Roosevelt testified, is essential to help protect American diplomats abroad. Restricting it severely not only would be a violation of international treaties, it would also invite retaliatory action by foreign governments.

None of this means that the U.S. government should sit still for these abuses of diplomatic privilege here -- and in fact, the government has not been passive about them. Actions have been taken to crack down on law violators. Offenders and, in the case of juveniles, their entire families have been expelled from this country. Diplomatic visas have been canceled and their holders' names entered into a computer system to guard against reentry. Written guidelines have been provided to police departments urging officers to complete investigations in order to be prepared for possible criminal prosecutions if offenders manage to reenter the country. Serious or numerous traffic offenses -- a single incidence of drunk driving for example -- will result in the loss of a driver's license. Firearms violations are grounds for immediate expulsion. And diplomats' children over 21, or students over 23, are no longer entitled to immunity.

Sen. Helms has apparently been persuaded that his bill would cause more problems than it would solve, and he has indicated that he is open to compromise. That's good. It is possible -- and important -- to be firm at home without jeopardizing the safety of American diplomats abroad.