The United States has never known quite what to do about Iran's role in anti-American terrorism.

Today's justifications of anti-Jewish and anti-Israeli terrorism can easily become tomorrow's justification of anti-American terrorism.

Saudi officials take offense at suggestions that the kingdom bears any responsibility for anti-American terrorism.

Mr. Ledeen wanted Iran to stop supporting anti-American terrorism.

Otherwise, a war could destabilize the region and "turbo-charge the recruitment process for anti-American terrorism," as one Saudi official put it privately.

With widely differing results, both authors seek to draw lessons for the future from the long history of anti-American terrorism.

It argues that Iran remains the "clearest case" of a state sponsor of anti-American terrorism as an element of its government's policy.

If the United States is serious about removing the sources of anti-American terrorism, then at some stage Washington will have to tackle the conflict in Kashmir.

That's all well and good, but President Assad of Syria is a major supporter of anti-American terrorism.

Although that nation is considered an ally, there have been troubling connections between it and anti-American terrorism.