The American withdrawal from Kabul in Aug 2021 made many people recall the scenes of the American withdrawal from Saigon in April 1975. That is indeed a helpful analogy, because the Taliban of today has similarities to the Vietcong of the past. Both are popular militia forces mobilized against American forces of occupation, only to establish authoritarian regimes after the latter’s departure. (The big difference, of course, is that while the authoritarian ideology of the Vietcong was communism, that of the Taliban is Islamism — a politicized and oppressive interpretation of Islam disfavored by the majority of the world’s 1.6 billion Muslims.)

Yet there is more to this historical analogy: In 1975, besides the Vietcong, there was another communist militia, which was much more fanatic and bloodthirsty: the Khmer Rouge, the worst of the worst among all communists, which would kill 2 million people in the next 3 years. It was finally overthrown in 1978, thanks to none other than the Vietnamese communists, who helped established a relatively more moderate regime in the neighboring Cambodia.

That old distinction between the Vietcong and the Khmer Rouge is somewhat similar to the new distinction between the Taliban and the “Islamic State,” or IS (including its local version, “IS-Khorasan,” or IS‑K). Yes, Taliban is savage. But since the IS is so much more savage, Taliban appears as a lesser evil, which may even help the U.S. and its allies against the worst of the worst.

Surely, the communist ideology shared by both the Vietcong and the Khmer Rouge (as as well the USSR and Maoist China) was a totalitarian menace that the West should have defeated — as it luckily did, to a great extent. But this defeat did not come thanks to American troops occupying communist countries one by one to “liberate” them. (If anything, that boosted communism, as in Vietnam.) Rather it came because communism was doomed to fail because its own deficiencies. All the West had to do — and rightly did — was to keep freedom alive and robust, to make its own democracies work well.

It is still what America should do today in the face of Islamist totalitarians: Just keep freedom alive and preserve liberal democracy, so most Muslims see (as many of them already do) that religious freedom is much better for them than religious tyranny. In the meantime, don’t forget that there are important shades and grades among whom you consider as the enemy. It can help devise wiser foreign policy.