Why sanctions (almost) never work: in the case of the late Idi Amin, they clearly helped drive him from power.

American policymakers frequently consider economic sanctions as a means of expressing disapproval of another regime or as a way of undermining that regime. Debates center around the efficacy of boycotts, especially if these are imposed unilaterally.

Idi Amin's death in August provides an opportunity to examine a case in which American sanctions contributed to bringing down his brutal regime as Uganda's dictator (1971-79).

While other governments have been ruled by terror. Amin's Uganda was almost in a category of its own. He attracted world attention by citing Adolf Hitler as his role model. His actions led to the deaths of approximately 300,000 people and the torture and economic deprivation of countless more.

During file first years of Amin's rule, American presidents and Congress did little more than denounce Amin and the flagrant human rights violations in Uganda.

The Congressional approach changed in 1977 when Representative Donald J. Pease (D-OH) determined to locus on Uganda. Pease, a freshman who had never set loot in Africa, became aware of the issue as a result of the efforts of William Goold, his legislative assistant, who had written his senior thesis at Oberlin College on Uganda's economy.

It became clear to Pease that Amin had virtually destroyed the Ugandan economy, beginning with the expulsion of all "Asians" (mostly of Indian heritage). Starting in September 1972, approximately 50,000 people of Indian origin were brutally uprooted from their homes and their properties seized. Uganda quickly missed the Indians' professional, business, and medical skills.

Pease and others in Congress determined that by 1977 the export of coffee had become almost the only Ugandan export and source of foreign capital. Funds from coffee sales were needed for oil imports and to pay Amin's soldiers.

Three senators, Mark Hatfield (R-OR), Lowell Weicker (R-CT), and Frank Church (D-ID), took the lead in that chamber. Church, who had responded favorably to a memo by this author, instructed his Foreign Relations Committee's Subcommittee on Foreign Economic Policy to investigate further.

Various House and Senate investigations confirmed that before Amin came to power in 1971, coffee earnings accounted for only 53 percent of total Ugandan foreign income, while by 1977 coffee sales provided 97 percent of Uganda's foreign income.

The United States and its allies purchased this collide in ever increasing amounts. By 1976, three fourths of all Ugandan coffee was purchased by the United States, the United Kingdom, France, Japan, West Germany, and the Netherlands, with the largest share going to the United States.

Congress further concluded that a U.S. boycott would have little effect on American consumers. Ugandan coffee account ed for only 4 percent of U.S. coffee imports in 1971 and 7 percent in 1977.

Despite adverse publicity, most American coffee companies refused to voluntarily stop purchasing Ugandan coffee. A representative from Procter & Gamble testified that they were not in the business of foreign policy. But when a House subcommittee passed Pease's first version of a boycott bill, the companies suspended their purchases.

President Carter signed a total trade ban into law on October 10, 1978. Amin was forced to flee in April 1979 when Uganda was invaded by Tanzanian President Julius Nyerere, who had mobilized a force of Ugandan exiles, dissidents, deserting Ugandan troops, and the Tanzanian army.

Although Church concluded that the congressionally imposed boycott "had a profound impact on internal conditions and contributed to the fall of Idi Amin," it is hard to attribute Amin's fall solely to the sanctions.

Still, as Hatfield stated, "U.S. withdrawal of purchases provided the psychological and practical ingredients necessary to complete a formula that would come to break Amin's seemingly invincible survivability. The U.S. embargo caused significant economic disruption."

Ralph Nurnberger served on the staff of the Senate Foreign Relations Committee during this period. He is of counsel at Preston Gates Ellis & Rouvelas Meeds, LLP, and teaches international relations at Georgetown University.