TURKEY RESPONDED promptly with new Cyprus proposals within days of the administration's request to Congress to lift the arms embargo on Ankara without demanding prior Turkish commitment on Cyprus. In this sense, the Turks met their share of the bargain that the administration had implied in deciding to unlink the Cyprus issue and the embargo issue. For the years that the two issues have been linked, Cyprus has remained half-occupied by the Turkish forces that invaded in 1974, and the embargo has weakened Turkey's defenses and curdled its taste for friendship and defense cooperation with the United States. Clearly, the time was ripe for a new approach.

Yet the new Turkish proposals do not necessarily signify the beginning of the end of either the Cyprus crisis or the NATO crisis in the eastern Mediterranean. The reason lies in the nature of those proposals, which cover the prospective territorial and constitutional relationship between Greek Cypriots and the Turkish Cypriot minority. As opening positions for a negotiation - and this is what the Turks privately said they were - they had a certain validity. The United Nation's Kurt Waldheim, the agreed middleman in the Cyprus situation, pronounced them "concrete and substantial." He did not, however, find them sufficiently fair and promising to ask the Cypriots, to negotiate on them. And the Cypriots, upon receiving the proposals from Mr. Waldheim in Vienna, went back to Nicosia and denounced them as "an effot to use the method of negotiation . . . under the chairmanship of the U.N. Secretary General, for the consolidation of faits accomplis." So it does not seem that Mr. Waldhiem has much choice but to go back to the Turks and ask them to look again at their offer.

Whatever he decides - and it should be known soon - Americans ought to keep a couple of things in mind. First, negotiations, Balkan-style, have resumed: The new Turkish package and the Cypriot rejection of it constitute part of a process that should be recognized and encouraged for the public sparring that it is. Then, this is not the moment for Americans to jostle the process, least of all by pushing quickly toward a congressional-executive showdown over the arms embargo. In such a premature showdown, the administration would quite likely lose, and that would doom all hope for Turkish relenting on Cyprus. Neither should supporters of the embargo leap to condemn Turkey for its first offer. An American public rebuke for the new Ecevit government's first steps on Cyprus could ensure it will attempt no more. It is a time for coolness and responsibility on all sides, and for crossed fingers.