But Syria is merely Act One. Next week, Act Two opens at the United Nations. There, we’ll see a charm offensive worthy of Richard III by the new Iranian president and veteran deceiver of the West, Hassan Rouhani. In response, the Obama administration will move on from punting in Syria to appeasing Iran. The diplomatic dance with Iran will be long and complex. But who doubts that the couple will end up where Iran, the leading partner, wants to go?

Smaller retreats lead to larger ones. The West’s failure to resist Mussolini’s invasion of Ethiopia in 1935—and his troops’ use of poison gas—was merely a foretaste of the failure to resist Hitler when he took the Rhineland in March 1936. In his essay in the volume Present Dangers, the historian Donald Kagan tells the story. Hitler had expected Britain to slap down Mussolini. When Mussolini asked for the loan of ships for his Ethiopian adventure, Hitler had privately said:

Let the Italians have a hundred ships! We’ll go back, undamaged. They will go through the Suez Canal, but they will never go further. The British navy’s battleship Repulse will be waiting there and signaling: “Which way are you going?” “South,” the Italians will reply. “Oh no you’re not,” the Repulse will reply. “You’re going north!” and north they will go.

There will be no Rhineland this time. Iran isn’t 1930s Germany, and the United States is more formidable than Britain. For now, Iran will have to achieve its goals by stealth and diplomacy, while Hitler achieved his by bravado and force. But the accommodation of the Islamic Republic of Iran’s quest for nuclear weapons lies ahead as surely as the accommodation of Nazi Germany’s expansionist dreams. Moreover, Rouhani knows what he is doing. He was Iran’s top nuclear negotiator for two critical years a decade ago and proved then his skill at duplicity in the furtherance of his regime’s nuclear ambitions.

And the Obama administration, too, will play its role, echoing the Baldwin government, which Winston Churchill in 1936 characterized as “decided only to be undecided, resolved to be irresolute, adamant for drift, solid for fluidity, all-powerful to be impotent.” Churchill continued, “So we go on preparing more months and years—precious, perhaps vital to the greatness of Britain—for the locusts to eat.”

As Iran moves closer to nuclear weapons, undeterred by the West’s leading power, a 21st-century tragedy threatens to unfold. Unless. Unless a dramatis persona who didn’t exist in 1936 intervenes: Israel. Ariel Sharon once famously said that Israel would not play the role of Czechoslovakia in the 1930s. Nor will it play the role of Poland. Despite imprecations from the Obama administration, Israel will act. One prays it will not be too late.

It is a strange course of events, heavy with historical irony, that has made the prime minister of Israel for now the leader of the West. But irony is better than tragedy.