Hobart Rowen hits a trenchant note in his "East Europe Wants In" {op-ed, April 26}. These recently liberated countries do indeed deserve to play a larger role in the affairs of the European Community. I share Mr. Rowen's disappointment that in the European Community's understandable drive toward completing a single, unified market by 1992, it is inadvertently putting a damper on the aspirations of Poland, Hungary, and Czechoslovakia. After 40 years of enforced isolation from the West, these societies passionately desire to play a major role in helping to build a new, more open and dynamic "Western" Europe.

Such concerns, needless to say, have direct and immediate relevance for U.S. policy toward the rapidly dissolving Soviet bloc as a whole. Based on a recent trip I took to liberated Europe -- including a long talk with the subject of Mr. Rowen's column, Bronislaw Geremek -- I am convinced that the future of economic reform in Poland, Hungary and Czechoslovakia rests on what risks the industrial democracies -- prominently including the United States -- are prepared to run on behalf of these recently liberated societies.

Of course, we should expect the EC to have a major say in helping launch its neighbors into the global trade and payments system. Geographic proximity alone makes such a partnership unavoidable and desirable. But the EC cannot and should not carry the whole burden. Geremek told me that he desires and expects the United States significantly to expand its trade and investment activities in his and neighboring countries; for economic and geopolitical reasons, we should be doing just that. And we have our work cut out for us. JOHN J. LaFALCE U.S. House of Representatives (D-N.Y.) Washington