Netanyahu accepts that history's lessons are not nice. The world, ancient and modern, is quite capable of snoozing as thousands perish, whether in Rwanda by edged weapons, Saddam Hussein's gassing of the Kurds, or, most recently, 100,000 in Syria.
Centuries before nuclear weapons, entire peoples have sometimes perished in war without much of a trace -- or much afterthought. After the Third Punic War, Carthage -- its physical space, people and language -- was obliterated by Rome. The vast Aztec Empire ceased to exist within two years of encountering Hernán Cortes. Byzantine, Vandal and Prussian are now mere adjectives; most have no idea that they refer to defeated peoples and states that vanished.
The pessimistic Netanyahu also remembers that there was mostly spineless outrage at Hitler's systematic harassment of Jews before the outbreak of World War II -- and impotence in the face of their extermination during the war. Within a decade of the end of the Holocaust, anti-Semitism and hatred of Israel throughout the Middle East had become almost a religion.
In the modern age of thermonuclear weapons, the idea of eliminating an entire people has never been more achievable. But collective morality does not often follow the fast track of technological change. Any modern claim of a superior global ethos, anchored in the United Nations, that might prevent such annihilation is no more valid now than it was in 1941. Again, ask the Tutsis of Rwanda.
The disastrous idea of a preemptory war to disarm Iran seems to us apocalyptic. But then, we are a nation of 313 million, not 8 million; the winner of World War II, not nearly wiped out by it; surrounded by two wide oceans, not 300 million hostile neighbors; and out of Iranian missile range, not well within it. Reverse those equations and Obama might sound as neurotic as Netanyahu would utopian.
We can be wrong about Hassan Rouhani without lethal consequences. Mr. Netanyahu reviews history and concludes that he has no such margin of error. That fact alone allows us to sound high-minded and idealistic -- and Israel suspicious and cranky.