FOUR YEARS AGO, three separate groups of Americans invited controversial foreigners to come to this country to speak. Those invited haven't yet been granted visas, but this week they came a little closer to making their trips. Tomas Borge, the interior minister of Nicaragua, was to be the guest of a group including members of Congress, university professors, journalists and religious leaders. Nino Pasti, a former general in the Italian army assigned to NATO who opposes the deployment of U.S. missiles in Europe, was invited to attend a nuclear disarmament rally in Boston. Olga Finlay and Leonor Rodriguez Lezcano, Cuban speakers on family law and women's rights, had been asked to lecture by the New York City Commission on the Status of Women. All four were turned down for visas by the State Department on the grounds that their presence in the United States would be detrimental to national security.

Suits were filed by those who had issued the invitations, and though they were unsuccessful in the trial court, the U.S. Court of Appeals for the D.C. Circuit ruled in favor of the plaintiffs, a ruling affirmed by the Supreme Court in a tie vote on Monday. Because of the tie, the holding applies only in this circuit, but since most litigation involving visa denials would be brought here under any circumstances, the ruling is important.

The appellate court had held that under the terms of the Immigration and Nationality Act, the State Department cannot exclude a visitor simply because he is affiliated with a Communist or other suspect political organization. A judgment must also be made that the visitor will engage in activities while he is here that would be detrimental to the national interest. Otherwise, Congress must be specifically notified of each visa denial. These are the guidelines set up by Congress in 1977, when the McGovern Amendment was passed to curb the power exercised by the executive branch to keep unpopular and controversial speakers from entering the country.

If the State Department can show in court that Mr. Borge, Gen. Pasti or Olga Finlay and Leonor Rodriguez are likely to incite riots, bomb buildings or smuggle arms from the United States, they will not be allowed to come here. But this is fanciful. And if, as seems far more certainly the case, the only reason for keeping them out was their status as members of certain organizations or the unpopularity of their causes, their entry should never have been viewed as a threat to the national security in the first place, but rather as evidence of that security.

Political affiliation and speech are not grounds for any penalty. The irony of excluding visitors because they have exercised rights that Americans cherish is obvious. A truly secure democracy cannot be harmed by a visitor's words or subverted by his political views. Let these visitors and others like them come to this country if they wish. The embarrassment was keeping them out