Last week, I wasn’t nice. Marking 45 years since the Munich Massacre, I compared Palestinian terrorists to Nazis. Barbarians who murder and castrate Jews – or applaud such evils – deserve that label. My column discussed the sobering lessons Palestinian terrorists taught when they killed 11 Israeli Olympians in 1972: antisemitism lives, Palestinianism often flirts with Nazism, and the world resents being disturbed by dead Jews.This week marks a morally complex moment: 35 years since the Sabra and Shatila massacre on September 18, 1982, during the first Israel-Lebanon war. If Munich reassured Israelis they were right, the Lebanon War forced them to confront themselves when they were partially wrong – and things went wrong.Survivalists frozen in Munich’s pain believe Israel can do no wrong; scolds obsessed with Sabra and Shatila’s injustices believe Israel can do no right. Like every democracy, Israel needs thinking patriots critical enough to fix what’s wrong while loyal enough to appreciate all that remains right.The Lebanon War is called Israel’s first war of choice. That historical truism is false and misleading. The 1956 Sinai Campaign was a judgment call too, while the 1982 war had a compelling and legal justification: neutralizing the PLO ’s illegal state within a state in Southern Lebanon. The PLO – whose charter seeks Israel’s destruction – had established a “thugocracy” menacing innocent Israelis and Lebanese. Lebanon degenerated from the Switzerland of the Middle East into its South Bronx.On June 3, 1982, a Palestinian assassin shot Israel’s ambassador to the UK, Shlomo Argov, in the head – paralyzing Argov, who suffered for 21 years until he died. Although these terrorists belonged to the Abu Nidal faction hostile to the PLO , prime minister Menachem Begin held Yasser Arafat and the PLO responsible. An “assault on an Israeli ambassador is tantamount to an attack on the state,” Begin explained. Israel bombed PLO assets in South Lebanon. The PLO shelled Kiryat Shmona, and “Operation Peace for Galilee” began on June 6, 1982.Begin originally expected to stop at the Litani River about 40 km. north of Israel, crush the terrorists, and withdraw. His defense minister, Ariel Sharon, pushed the IDF forward to Beirut, determined to banish Arafat from his headquarters there. Crossing the Litani and starting to besiege Beirut on June 14 was the first big mistake.This move expanded the mission and the messiness – staining Israel’s reputation while enmeshing Israel in Lebanon until 2000.Throughout the summer of 1982, international criticism of Israel for imposing unnecessary suffering intensified. Then, on September 16, Christian Phalangists allied with the Israelis murdered hundreds of Palestinians in the Sabra and Shatila refugee camps. The Phalangists were avenging the murder of their leader, Bachir Gemayel, Lebanon’s president, in a car bombing two days earlier.Begin dismissed the international fury, saying: “goyim kill goyim and they blame the Jews.” He was half right and completely wrong – meaning partially accurate but morally off. True, Phalangist killers committed the crimes. But, as Israel’s internal review, the Kahan Commission, concluded in forcing Sharon’s resignation, Israel was “indirectly responsible.” Israel controlled the area. Deputy prime minister David Levy warned his Cabinet colleagues that Phalangist vengeance would be brutal and world opinion, unsparing. Like today, Israel was neither guilty of the worst crimes it is charged with, nor fully innocent either.Rosh Hashana that year fell on September 18 and 19. After a summer of reports treating Lebanon as Israel’s Vietnam, an unnecessary evil, Sabra and Shatila seemed to be Israel’s “My Lai Massacre,” a deliberate crime.Many Jews lamented that holiday weekend: is this what Zionism wrought? Four hundred thousand Israelis protested – resulting in that Kahan Commission.Leonard Fein, the legendary columnist, defined two kinds of Jews in Moment magazine: one obsessed with protecting Jewish bodies, the other with preserving the Jewish soul. “And the trouble is,” he confessed, “most of us are both kinds of Jew” – and Zionists: “We want to be normal, we want to be special: we want to be a light unto the nations, we want to be a nation like all the others.” Fein was a moralist, willing to risk a “nervous breakdown” balancing the two impulses.Unfortunately, 35 years later the Jewish world is increasingly polarized.Most Jews are jugglers, balancing power and morality, survival and purity, the body and the soul, in a dangerous world. But Sabra and Shatila spawned new generations of Jews and non-Jews who go for Israel’s jugular.The Lebanon War soured these critics on Israel, treating Israel as the mass murderer, not the flawed bystander – the first of many exaggerations demonizing Israel.These scolds are so busy breast-beating they never get around to chest-thumping; the Jews among them hate so many Israeli actions many forget to love their state too.These Jews, preoccupied by the occupation, are in perpetual finger-pointing mode. In their zeal to perfect the Jewish state, they overlook that, first, the Jewish state must survive its amoral enemies. Today, they may call themselves the Jewish voice for peace – but they represent a marginal minority of elites prescribing suicide.If given today’s false choice between learning the watch-your-back lessons of Munich or the Blame-Israel-first lessons of Lebanon, I start with Munich. We can’t be pure if we don’t survive. But I’m with the late Leonard Fein – let’s risk the nervous breakdown and navigate the world’s messiness – aspiring to be good, after ensuring we stay alive.The writer is the author of The Age of Clinton: America in the 1990s. His forthcoming book, The Zionist Ideas, which updates Arthur Hertzberg’s classic work, will be published by The Jewish Publication Society in Spring 2018. He is a Distinguished Scholar of North American History at McGill University. Follow on Twitter @GilTroy.