What’s wrong with central casting? It’s a virtual truism: The United States always seems to pick the wrong guy to star as George Washington in some faraway civil war. We sell him weapons for self-defense against his despicable foes — and then, sometimes before the end of the first battle, we find we are committed to a bad actor who bears an uncanny resemblance to Genghis Khan.

President Barack Obama just approved the sale of 24 Apache helicopters to the Iraqi government of Prime Minister Nouri al-Maliki — despite well-founded concerns that Maliki may use them against people we do like as well as those we don’t.

Helicopters aren’t the only munitions on Maliki’s shopping list. Washington has negotiated the sale of 480 Hellfire air-to-ground missiles, along with reconnaissance drones and F-16 fighter jets.

To hear Maliki tell it, he needs these weapons to stop terrorists from destroying his democratically-elected government. To hear his opponents, the divisive Maliki creates his own problems by hounding legitimate rivals, favoring Shi’ites over Sunnis and fueling sectarian grudges. To hear Obama, Maliki is America’s only option: Support him, or see Iraq spiral into civil war.

All three scenarios are correct. They almost always are.

Desperate leaders of unstable countries are problematic partners. They’re controversial with their own people. Backing them typically involves deep moral compromises. And, boy, we’ve picked some doozies in the past: from Vietnam’s Ngo Dinh Diem, to Taiwan’s Chiang Kai-shek (and the notorious Madame Chiang Kai-shek), to Haiti’s Jean-Bertrand Aristide, to Iran’s Reza Shah Pahlavi, to Afghanistan’s Hamid Karzai.