Source: The New York Times Contact: July 15, 1997 Japan, Too, Struggles With Methamphetamine To the Editor: The Brooklyn drug dealer you quoted on the relative disadvantages of selling methamphetamine as compared with crack cocaine (news article, July 8) could take some pointers from his Japanese counterparts. Although crack users may "come back every two hours," sales to a methamphetamine user offer a greater profit margin, attract a broader customer base and tend to be a lower priority for law enforcement officials. Japan's 50year drug war against methamphetamine reveals the intractability of the trade. Even when Japanese authorities successfully curtailed domestic production during the 1950's, organized crime groups turned to suppliers in Korea and Taiwan, and, by the 1990's, China. H. RICHARD FRIMAN Milwaukee, July 11, 1997 The writer is an associate professor of political science at Marquette University. To the Editor: Four key words in your article "Mexico and Drugs: Was U.S. Napping?" (front page, July 11) indicate why no drug interdiction effort is likely to succeed: "the thriving American market." That, unfortunately, is one instance where our market economy works all too well to our social detriment. JOE LESLY HastingsonHudson, N.Y. July 11, 1997 Copyright 1997 The New York Times Company