Lisbon — PORTUGAL'S new man at the helm approaches a set of awesome problems with brimming self-confidence. Anibal Cavaco Silva is, as he quickly tells you, the first Portuguese prime minister who is not a lawyer. He is a lean and athletic man (he was a university hurdling champion and is today an avid jogger), and an economist by profession. He thinks he has a program to revitalize Portugal's sagging economy, the No. 1 problem. The challenge is formidable, for although Mr. Cavaco Silva's Social Democratic Party outpointed other parties in last month's elections, he still heads only a minority government.
Undaunted, Prime Minister Cavaco Silva thinks he has a window of opportunity of about a hundred days. He is gambling that the other parties will not block him, on grounds ``there is no other alternative. They know they cannot form another government without the communists,'' who took 15 percent of the recent vote.
Basically he wants to move away a little from the economic belt-tightening that did in his predecessors, the Socialist Party of M'ario Soares.
This has to be done while keeping Portugal's foreign deficit under control. Cavaco Silva thinks he can promote investment. Last year capital investment dropped 20 percent. He favors private enterprise and a free-market economy, and he thinks he can persuade entrepreneurs to keep their money in the country and take risks on behalf of expansion. But it is not now possible to denationalize, he says sadly; he does, however, favor ``disinvestment in some companies.''
He wants sweeping changes in the monetary and budgetary systems. He knows he is battling public disillusionment from a string of economic setbacks that started when Portugal threw off totalitarianism a decade ago.
He seeks new markets for Portugal. During his national service he was an Army officer in Mozambique and is clearly fascinated by the prospect of developing trade relations with Africa. He says the Japanese are interested in Portugal. He hopes the Americans will be, too, and he believes Portugal's pending entry into the European Community offers opportunity.
He thinks some of this can be done with his tenuous minority foothold in parliament, but believes a review of the present constitutional setup is essential. Many other politicians, of differing parties, agree.
Proportional representation in Portugal discourages the emergence of a party with a clear-cut majority and the ability to rule. The result has been a series of coalition governments. Says a foreign diplomat: ``Have a dinner party for 10 Portuguese, and eight of them will have been prime minister or a Cabinet minister.''
Authority is also divided among a president, who is chief of state, a prime minister, who is head of government but hobbled by party fragmentation, and parliament.
There is opportunity for change next year when the present Constitution is up for review. It could be modified by a two-thirds vote of parliament. The outgoing President of Portugal, Ant'onio Ramalho Eanes, would like to see more authority given the prime minister. He seems to be reflecting the viewpoint of others in Portuguese politics who talk of a West German-type chancellorship for Portugal. Former Premier Soares concurs that there is need for change. ``We want majority government, excluding extremi sts of both sides,'' he says. ``We need reform without creating the danger of breaking up democracy.''
Before there can be movement on such changes, Portugal must undergo elections for mayors and councilmen in December and a probable two-round election for the presidency beginning in January.
In both economics and politics, Portugal faces a couple of delicate months ahead.
John Hughes is a Pulitzer Prize-winning journalist who was assistant secretary of state from 1982 to 1984.