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Outrage over the Iranian government's violent suppression and intimidation of dissent has appropriately produced considerable concern in the United States and fueled a debate over U.S. policy toward Tehran. Many political leaders and pundits have called for more active and vocal American support of the Iranian opposition, typically on the basis of analogies to oppressive regimes of the twentieth century.

Unfortunately, the vast majority of these analogies are misleading and even dangerous if used as guides to policy. The historical cases most similar to present-day Iran should instill caution.

Some have compared Iran to the Philippines in 1986 or South Korea in 1987, both cases in which the Reagan administration lent support to domestic groups pressing for greater...