Reagan whirs through Rome and Vatican

President Reagan carried his continental tour to Italy June 7, with his own version of a Roman political crossroads clearly in view--a dual emphasis on European and domestic US audiences.

Aboard his modern chariot Marine One, he darted from the Vatican heliport and an audience with Pope John Paul II (telecast live in Europe) to the Quirinale Palace to meet Italian President Sandro Pertini, then to the Chigi Palace for lunch with Prime Minister Giovanni Spadolini--rounding the Roman political circuit in less than five hours. Brief though it was, Mr. Reagan's visit to Rome was a personal high.

''He has long wanted to meet the Pope,'' a Reagan aide told the Monitor. ''He admired the Pope when the Pontiff visited Poland in 1979. Reagan watched the Pope's visit to the US day after day on TV. He considers the Pope a great leader , a great antitotalitarian.''

Beyond this personal interest, the papal visit did reflect a blend of ethnic and denominational politicking abroad, for the American President.

An obvious political factor behind the Vatican visit, is the fact that 24 percent of American voters identify themselves as Roman Catholic. But there is an ecumenism to Reagan's European travels on this score. He next visits Britain and West Germany, seats of nonfundamentalist Protestant denominations such as the Episcopalians and Lutherans, who make up 27 percent of the US voting public.

Ethnically, too, the greater links with immigrant nationalities in the US still lie ahead on the Reagan itinerary this week. Some 11.7 million Americans identify themselves as having at least partially Italian roots, and 8.4 percent Polish, the nationality of the Pope. This is less than half the 52 million Americans who claim German ancestry, and the 40 million who claim English ancestry.

But to Italian and American foreign policy experts, the Italian visit would have been justified purely for European security and political reasons.

Italy has become one of the most enthusiastic supporters of the NATO alliance and European integration. It was one of the first European nations to offer sites for the new US-made theater nuclear weapons.

Referring to Italian sensitivity about its status as a European power, an Italian diplomat told the Monitor: ''That Mr. Reagan would include Rome in his visits to Paris, London, and Bonn confirms our American friends' appreciation of Italy as one of the four major European partners of the US.''

With the Socialists contending to lead a new government, Reagan's trip is useful to secure the American-Italian line. Italians point out that the Socialists also support stationing cruise missiles on Italian soil, to emphasize that no change in Italian foreign policy is expected.

State matters aside, the personal drama of the American President and the Polish Pontiff, both survivors of assassination attempts, meeting here aroused the Italians from their usual indifference toward visitors.

''Romans are used to people passing through,'' said an Italian official. ''Reagan and the Pope are both similar. Both are ideologically orthodox--the Pope on religious matters, Reagan on his military and economic agenda.

''There is one difference: the Pope is a social radical, Reagan is not. The Pope is open to the distribution of income. Reagan has the bearing of the rich, the Pope the modesty of the poor.

''Both are sticking to their dogmas. The Pope is extremely dogmatic for Catholics today. Reagan may prove too dogmatic on social and economic issues for Americans and Europeans.''