The sign at the entrance bears a menacing, "watch out for the dog," message so the approach of a tiny, gapping dacshund is something of a surprise. Not so the appearance of its owner, journalist Luigi Barzini. In slacks and a cashmere V-neck, Barzini at 71 looks only a bit grayer than he did 15 years ago when publication of his book "The Italians" established him as something of a divine on his countrymen's ways.

"The Italians haven't changed either," says Barzini, adding that the people of whom he has become an authority are still characterized by "private virtues and public vices."

On the eve of important national elections, they still are suspicious of their politicians and government, are still looking for a "gimmick with which to solve the dilemmas of Italian politics, and they still have no concept of the res publica , or the common good."

Even if Rome, once miles distant, has crept annoyingly near, the red-walled villa with its seven acres of garden and luxuriant woods where Barzini has lived since 1949 is substantially unchanged.

Barzini spends most of his time in his Via Cassia oasis, reading and, of course, writing. The latest project is a new book called "The Europeans."

On the recent summer day-with the scrape of a gardener's shovel submerged by the twittering of swallows-a visitor found Barzini relaxed and, more than pessimistic, resigned.

"Italy is a glorious, gilded galleon with holes in the hull that sits in the mud. It can't go anywhere, but then again it can't sink either," he says, resorting to an analogy used to console Americans dismayed by his lectures on Italy's ills.

Seated in a worn red leather chair in his cool studio garnished with home-grown roses and pictures of the horses he once owned, Barzini appears convinced that Italy will muddle through. But it won't be easy, he adds, using a gold-tipped ivory cigarette holder to make his point, "because historically the Italians have always been tempted to enroll the arsonists in the fire brigade."

In the years before fascism, a series of liberal Italian governments used "transformist" policies to absorb their enemies, which was easier than defeating them. In the 1960s, the ruling Christian Democrats tried this with the Socialists. Now, says Barzini, the number one question is whether the powerful Communist Party should be allowed to rule together with the Christian Democrats.

The Commuists, the country's second-largest party, recently decided to end three years of parliamentary cooperation with the Catholic Christian Democrats unless they get Cabinet seats after the June 3 election.

Bringing in the Communist now "would be premature and possibly dangerous," Barzini insists.

Although Barzini is convinced many Communists are "in good faith" and that the party's contact with the democratic West has greatly changed it, in his opinion Italy's Marxists "are still reluctant to abandon their heritage and their myths. When you ask them what sidee they would be on in World War III, they don't give you a clear answer."

Not all Italians share Barzini's view-point. In the last election three years ago, 12 million Italians-more than a third of the voting population-voted for Communists. This time, however, the forecasts are less favorable for the giant party.

Barzini is one of many Italians who believe their country's major problem is the absence of a strong Socialist Party that "could free the country from Christian Democratic hegemony."

"Ours," he says, 'is incapable of deciding whether it is fish of fowl. It is good only at divisions, inner-party polemics and splits."

"I suppose they'll change," he adds, "but that might be a long time off."

Barzini believes that Italy's development as a modern state has been retarded by the fact that in place of the liberal and socialist parties that dominate politics elsewhere, it has Catholics and Communists instead.

"What do either of those two groups know about running an advanced industrialized nation?" he asks.

"But Italy isn't a modern state," he responds to his own question.

Exchaning ideas with his visitor over glasses of cold vichy water, Barzini makes it clear that the coming election is only one chapter. The basic problem is instead "the state of the state," a condition in which services provided by most modern societies-hospitals, mails, prisons, schools, universities and police-are in a pronounced state of decay.

A glance at the Barzini dining room with its elaborate mosaic floor-the table is set for lunch and a salad of artichokes, lettuce and radishes sits waiting in a silver bowl-makes it clear, however, that for the time being at least the decay has kept its distance from Villa Cassia.

Even in an era of frequent kidnaping-so far this year there have been 27-Barzini keeps his cool.

"I take no precautions," he says, "but I have left written instructions that should I be kidnaped not a single lira is to be paid."

The talk of kidnaping brings to mind that at the end of a long interview Barzini has not mentioned the one issue-terrorism-that automatically comes to mind whenever Italy is the subject of conversation.

"Terrorism is a secondary issue," says Barzini. "Anyone who shoots and kills at random has already admitted defeat."

A year ago when former prime minister Aldo Moro was kidnaped and then murdered by the Red Brigades, Barzini speculated that the shock might cause the Italian people to pull together for once. But that did not happen.

The major result was the coming elections, which promise few real fluctuations and an immediate future characterized largely by confusion. So what is the solution?

"It's like being in Constantinople and being asked that question just as the Turks are climbing the walls. I don't know," Barzini adds whimsically. "Perhaps the Turks will win." CAPTION: Picture, LUIGI BARZINI . . . Italy seeks gimmick