A former member of a Reagan foreign affairs advisory group criticized the current administration's "casual" foreign policy at a Center for International Affairs seminar yesterday.

Speaking to about 50 people, Robert W. Tucker, professor of international relations at Johns Hopkins University, said that President Reagan's foreign policy suffers from a lack of leadership and is not very different from that of former president Jimmy Carter.

Tucker, who has recently published several articles in the political journals Foreign Policy and Commentary, described Reagan's global vision as very simple and belonging to an old order. Reagan wants to return to a pre-Vietnam situation, he added.

The realities of the world situation are moderating Reagan's foreign policies and will soon tone down his rhetoric, he predicted, explaining that the policy Reagan advocates of global containment of the Soviets needs military superiority and complacent allies to succeed--neither of which the United States has.

In addition, the administration considers foreign policy secondary to domestic and economic problems, and memories of the Vietnam experience still make Americans wary of becoming involved in war, Tucker added, citing the alarm over El Salvador last spring.

During the question session, Tucker expressed concern about recent pacifist developments in Western Europe. He called the decision to deploy new American nuclear missiles in Europe a great error, adding that conventional forces would have been just as effective and less threatening to Europeans.