Lisbon — Portugal and Spain, uneasy neighbors in Europe's strategically important Iberian peninsula, have moved to overcome centuries of mutual mistrust. The Socialist leaders of the two countries - which between them house five American and one West German military base - held an unprecedented summit in Lisbon last weekend aimed at breaking the ''psychological'' barriers to better relations.
The predominantly Roman Catholic neighbors have much in common, yet for historical reasons, disregard and suspicion have marked their dealings for 600 years.
Portugal is a founding member of the North Atlantic Treaty Organization, but Spain has yet to commit itself fully to the pact. Analysts say the Iberian peninsula, commanding the southwestern approaches to Europe, is vitally important to the Western allies. In this context, Western diplomats here note, any improvement in cooperation is important and should be actively encouraged by the alliance.
But NATO was low on the agenda when Portugese Prime Minister Mario Soares and his Spanish counterpart, Filipe Gonzalez, sat down for two days of talks.
They had two concrete problems to resolve: a fishing dispute that has led to frequent clashes on the open seas and angry exchanges between Lisbon and Madrid, and a trade balance disproportionately favorable to Spain. The two Socialists also joined forces for an offensive on French-led stalling over admitting Portugal and Spain to the European Community.
They made little progress on the first two issues. Nevertheless both leaders were manifestly satisfied with the outcome. Mr. Soares summed it up by saying that 600 years of prejudices could not be swept away in two days but that the foundations of a modern relationship had been firmly laid.
The two governments agreed to set up a permanent secretariat to deal with bilateral issues and to meet annually at prime ministerial level for fuller consultations. Soares and Gonzalez signed a 15-page document, called the Lisbon Declaration, which outlined the principles for cooperation on a number of topics.
A breakthrough in the fishing dispute, vital to Spain's large commercial fishing fleet, is likely to come only next year when Madrid and Lisbon sit down to negotiate a new treaty. Meanwhile, the ban on Spanish trawling for shellfish inside Portugal's 12-mile exclusive zone is certain to lead to renewed hostilities on the high seas.
The two neighbors, which will enjoy barrier-free trading once they are inside the EC, agreed to relax tariffs. This should make it easier for Portuguese goods to enter the protective Spanish market and help reduce the massive trade imbalance.
They pledged to keep the peninsula free of nuclear weapons while honoring commitments to Washington on Spanish bases and Portugal's agreements on facilities for NATO and the United States.
The most significant development was the decision to adopt a tough joint approach to the difficulties plaguing negotiations for Portuguese and Spanish entry to the EC.