Pubdate: Mon, 11 Dec 2000 Date: 12/11/2000 Source: Business Week (US) Author: Robert Sharpe If U.S. drug warriors succeed in their Sisyphean task of eradicating the supply of coca in South America, domestic methamphetamine production will boom to meet the demand (''The war on coca: How far will the U.S. go?'' International Business, Nov. 20). Thanks to successes at eradicating marijuana overseas, a resulting increase in domestic cultivation has made marijuana America's No. 1 cash crop. As long as there is a demand, there will be a supply. Destabilizing entire countries will not make America drug-free, but sensible regulation could feasibly undermine the volatile black market. As the most popular illicit drug, marijuana provides the contacts that introduce Americans to harder drugs. This ''gateway'' is a direct result of marijuana's illegal status, not the plant itself. Illegal drug dealers do not I.D. for age, but they do push more profitable, addictive drugs such as cocaine or heroin when given the chance. Regulation is desperately needed to restrict access to drugs. As counterintuitive as it may seem, replacing marijuana prohibition with regulation would ultimately do a better job protecting children from drugs than funding civil war in Colombia. Robert Sharpe, Lindesmith Center, Drug Policy Foundation Washington