Athens — Greece's new opposition leader, Constantine Mitsotakis, said last week that his country must ''start a dialogue'' with its long-time adversary, Turkey. In a Monitor interview, the former foreign minister charged that Socialist Prime Minister Andreas Papandreou's claim that he has nothing to discuss with Turkey is ''clear and pure irrationality.''
Talks with Turkey would be a first step toward solving bilateral problems that have severely damaged NATO's cohesion on its southern flank, he added. Last week, for example, Mr. Papandreou closed a major air corridor over the Aegean Sea to commercial traffic because of a quarrel with Turkey and NATO over alliance maneuvers in the area.
Mr. Mitsotakis, who was elected leader of the New Democracy Party a month ago , also accused the Socialist government of setting up a ''police state'' and running a ''fascist television'' system.
With national elections due within a year, he faces a formidable challenge in his efforts to unseat Papandreou, according to political and diplomatic observers. Still, New Democracy came within 6 percentage points of Papandreou's Panhellenic Socialist Movement (PASOK) in June's elections for the European Parliament.
Widely viewed as being as dynamic and politically skillful as Papandreou, Mitsotakis must quickly gain control over his party, which has been torn by internecine disputes since it lost power to PASOK in 1981. And he must make a strong case to convince the electorate that his pro-American policy is not, as Papandreou claims, a sellout of Greek interests and independence.
Finally, these observers say, he must overcome his own political past.
A tall, imposing figure, Mitsotakis fits the traditional mold of a Greek national leader. Born into a prominent Cretan political family, Mitsotakis was elected to Parliament with the Liberal Party at the age of 28. He later joined the Center Union Party and was finance minister in the cabinets of the current prime minister's father, George Papandreou, in 1964 and 1965.
During a political crisis in 1965, Mitsotakis and a number of other Center Union members of the Cabinet defected from the government, forming a minority government with conservative support. His role in the so-called ''apostates'' government earned him the label of opportunist and the suspicion, if not hatred, of many in Greece, including Andreas Papandreou, another minister in George Papandreou's Cabinet.
When Mitsotakis was elected leader of New Democracy last month, the prime minister lashed out, calling him a ''traitor'' and a ''nightmare'' and blaming him for the 1967-74 military dictatorship and the events that led to the Turkish invasion of Cyprus in 1974.
A pro-government newspaper ran a special series on the 1965 crisis, highlighting Mitsotakis's role. Papandreou would like to keep the spotlight on Mitsotakis, a trap Mitsotakis is acutely aware of.
Mitsotakis has taken over a party whose leaders had governed the country for most of the postwar period until 1981. In the last New Democracy government, he was foreign minister. As one party member put it, ''We lost touch with our party base and with the people. After we lost, we had nothing to fall back on.'' Mitsotakis has moved quickly to identify his party with the political center, describing his ideology as ''radical liberalism.''
New Democracy faces a problem in convincing the voters to trust it to solve the country's acute economic problems, as the economy had begun a downward spiral two years before Papandreou took over. Mitsotakis says, however, that his party has gained credibility by admitting past errors. He says it is formulating a program based on private enterprise and the free market. An aide described his domestic policies as rightist on economic policy and progressive on social policy.
He pledges, as all Greek political candidates do, to curtail the country's huge and inefficient bureaucracy, whose stifling effects on business initiative is legendary. But, he says, ''You cannot have new investments if the private sector does not know the rules of the game. Today nobody trusts the present government. This is a crazy government. It says one thing and does another.''
The area in which Mitsotakis may have the hardest time winning over the electorate is foreign policy, where polls show Greeks support Papandreou, if not his policies. Unlike the prime minister, Mitsotakis has always been strongly pro-West and pro-Europe. And he has asserted that normalizing relations with Israel would be one of the basic objectives of his Middle East policy.
He strongly supports the position of all Greek governments since the fall of the dictatorship in 1974 that the regional balance of power with Turkey must be maintained, a view that has led to yearly clashes between the White House and Congress over the allocation of military aid to the two countries.
Stating that the problem of Cyprus could be solved quickly if only Turkey showed the necessary good will, Mitsotakis wonders, ''why the US does not do what it could do'' to ''influence Turkey to show some logic.''
He also does not rule out the possibility that a New Democracy government might withdraw from NATO maneuvers in the region because of disputes with Turkey. But he dismisses the claim of some that a Conservative government might be forced by popular opinion to fulfill Papandreou's promise to close US bases on Greek soil at the end of the decade if Greek-Turkish disputes and the Cyprus problem are not resolved.
''Those bases are useful because they contribute to the balance of power (in the region) which is a fundamental objective of Greek foreign policy,'' he maintains, ridiculing the government's assertion that the base agreement signed in July of last year required their removal.
No Greek believes that ''fairytale,'' he says. But polls indicate that this position will win him few votes, as a majority of Greeks express hostility to the US bases.
New Democracy knows it must get its message across to the people. But getting in the way, says Mitsotakis, is government control of television. ''Even if we had a formal dictatorship, New Democracy would not have suffered more than it does presently in the domain of television,'' he said. He also accuses the government of instituting a ''police state ... that is, persecution, police terrorism, and political graft'' to intimidate voters.