THE SITUATION in the eastern Mediterranean is dismal. Turkey's forces continue to occupy a disproportionate share of Cyprus, and Turkey's politicians continue to block negotiations that would restore the unity of the island nation and make possible coexistence between Turkish and Greek Cypriots. At home Turks indulge a cultural identity crisis whose prolongation takes Turkey ever farther from its post-War Western orientation. Meanwhile, the United States is still locked out of Turkish bases that are important to the defense of the whole Western alliance. The Greeks, mistaking for partiality the Carter administration's efforts to play the careful broker toward Turkey, sulk. The possibility out of a local war between these two NATO partners, arising from their dispute over demarcation of the continental shelf in the Aegean Sea, cannot be rule out.

The Carter administration started out its term with as reasonable a plan as circumstances in the eastern Mediterranean permit. It tried to convince Turks of its good faith by authorizing new military sales and accepting in principle the $1 billion bases agreement negotiated with Ankara by the previous administration. At the same time, it sought to accumulate bargaining power by condition its submission to Congress of the bases agreement on Turkish compromise on Cyprus. But Congress, playing its familiar spoiler's role, undercut the administration. In a power play as misguided as it was sell intentioned, elements acting in the name of Greece - though perhaps not ot its ultimate benefit - threatened to remove much of the administration's bargaining power with the Turks. The administration, in an unbecoming failure of nerve, acquiesced.

So the focus moves to Ankara, where elections are to be held on June 5. The key question is not whether Prime Minister Demirel or ex-Prime Minister Ecevit wins but whether either can secure the absolute majority that would let him rule without dependence on the anti-Western National Salvation Power, which wields the balance of power. As resentful as they are of what they see as gross American insensitivity, Turkish politicians like Mr. Demirel and Mr. Exevit are not oblivious to Turkey's long-term advantage in developing in league with the West. Either one, with mandate, could conceivably make the small gestures that would start to break the Cyprus deadlock. Meanwhile, Washington stands ready to mediate the ticking Aegean dispute. With a great deal of diplomatic skill and luck, and a little more recognition by Congress of its responsibilities, the summer could bring better days. One hesitates to contemplate the alternative.