In an era of weak coalition governments, the rule of Greece's Constantine Karamanlis is an exception. Karamanlis commands an overwhelming parliamentary majority. A conservative, he has not been challenged by the left, and he has been described as the bulwark between democracy and deluge.

Yet, this is a political society traditionally torn by chaos and tyranny. There have been eight major military upheavals here since World War I, so the question arises: Can Greece's fledgling democracy survive without the 70-year-old premier.

Diplomatic and political opinion is divided as the country prepares to celebrate the third anniversary of its return to civilian government on July 23.

After seven years of dictatorship, from 1967 to 1974, the nation now faces the traditional political dilemma associated with virtually single-handed rule.

There is the specter of yet another coup by hawkish, ambitious officers when Karamanlis steps down. Standing by are disgruntled buccaneer capitalists who flourished during the junta years. The political opposition is divided and quarrelsome and Karamanlis has not designated an heir.

Beneath the surface, are all the elements of turmoil, but advisors to the premier are hopeful that he will leave a legacy of moderation.

"Karamanlis detests passion in politics, and has said that it is the curse of our race," one of his closest aides observed. "His own formula for a successful democracy is that national issues should not become party issues and party issues should not become personal issues. He has risen above party politics and is a national leader."

"Stability has not been one of our characteristics in the past," he said, "but I hope we have learned the lessons of dictatorship, and that our mentality has changed -- not just the people, but the leadership of the political parties, the trade unions, the intellectuals and the press."

Whether the country's institutions will be able to preserve its new democracy is questionable in the view of one diplomatic official.

"It depends to a great extent on the people, the first post-Karamanlis government, and the political climate then," he said. "If there is economic chaos, riots in the streets, then I don't think the country's institutions will hold Greece together, and the military could intervene. This is not an American or British-type democracy with safeguards built into the system. It's a democracy of Karamanlis."

The aloof and complex premier, who has dominated Greek politics for the last 20 years, defends his paternalistic leadership as the only way to rule the volatile Greeks. He believes that a strong personality is essential to leadership and has an arithmetical formula for success.

"The rich must sacrifice 30 per cent of their wealth for moral equity and social programs," he told a recent American visitor, "and the majority must sacrifice 30 per cent of their freedom to prevent amarchy."

His political opponents argue, however, that such philosophy must be accompanied by strong institutions, and they do not think that Greece has developed them.

"Our key mechanisms -- the armed forces, and security services, the administration and the courts -- have no elasticity to adapt themselves to new situations," said Leonidas Kyrkos, parliamentary spokesman for the moderate Communist Party of the Interior.

"In England, institutions and developments go hand-in-hand. Here what is abnormal is that some highly discredited and compromised junta supporters are being used. There is consequently the potential for confrontation, with traditional rightist elements controlling the structure, and progressive and liberal political forces in the forefront of a growing movement for change."

There are recurring reports of discontent within the army, by tradition a strongly politicized force.

Constantinos Badouvas, an opposition member of parliament, has charged that the government has ignored three recent conspiracies to kidnap or assassinate Karamanlis. The government denied this but has acknowledged that four plots threatened the premier during the first six months of his rule.

Western diplomatic officials believe it is highly unlikely that the army, as an organized unit, would move against Karamanlis, although "one Western ambassador said that a new confrontation with Turkey could create such a threat.

There are still pockets of resistance within the armed, according to an anti-junta, retired senior officer, and he described their mood as "ambivalent and stratified."

"Take a young major, for example, who is weaned by the dictators to believe that a strong, military-revolutionary government is mandatory, he said. "These officers were extremely nationalistic. Then they faced disaster after seven years.

"They were impotent against Turkey on Cyprus. They couldn't even mobilize. Then came the Karamanlis government which whipped them into a topnotch fighting force. They now have the best training, standards and equipment that we've ever seen in Greece. So, in their mind, what takes priority? That's the essential question. Being a good professional army or the so-called saviors of Greece?"

Panayotis Lambrias, undersecretary to the Premier and one of his closest aides, minimizes the threat of military.

"At the risk of oversimplification," Lambrias said, "I think the greatest threat to democracy will be if a trend develops to negate Karamanlis' policy of removing passion from politics and exercising restraint.

"If for reasons of demagogic pressure or political animosity, the present stability is reversed, it would be catastrophic. But this time, as opposed to 1967, it would be very difficult for the military to intervene -- primarily because by then we hope to be integrated into the Common Market. Isolated countries are much more easily threatened than a country belonging to a larger European order, such as the EEC."