Back in 1953, an Egyptian army officer was asked by the magazine Al-Musawwar what he would write to Hitler if he were still alive. “My Dear Hitler,” he began gushingly, “I admire you from the bottom of my heart.” He proceeded to extol the German dictator for, among other things, creating dissension between “the old man Churchill and his allies, the sons of Satan.” If the mass murder of Jews bothered the officer in the least, he did not mention it. Years later, as the president of Egypt, he was himself murdered for making peace with the Jewish state. His name, of course, was Anwar Sadat.

The peace that Sadat manufactured is now unraveling, a thread here, a thread there. The Israelis and the Egyptians have traded insults of all sorts, and now the Israeli Embassy, always an edifice constructed out of wishful thinking, has been sacked by a Cairo mob. The Israeli ambassador is gone, and when he will return, if ever, is not clear.

The Israeli-Egyptian peace is in jeopardy, and so is the cordial rapport Israel once had with Turkey. Along with Iran and Ethiopia, Turkey helped make up what was called “the strategy of the periphery,” the relationship that Israel’s founding prime minister, David Ben-Gurion, established with non-Arab nations. But Iran now is Israel’s mortal enemy, Ethiopia hardly matters and Turkey is bristling with hostility. Ankara wants Israel to apologize — not merely express regret — for its perfectly legal attempt to turn back a so-called humanitarian flotilla heading for Gaza last year. Nine people died. Israeli forces overreacted and now Turkey is doing the same.

Israel’s dilemma is that the Middle East, for all the talk of revolution, is slipping backward. Turkey is possibly evolving into an Islamic republic and even if this is not the case, it is reasserting its historical role as a regional power. Iran toppled its modernizing, Westernizing shah with his pro-Israel proclivities and in 1979 became a theocracy. And Egypt, long the leader of the Arab world, may find it cannot lead its own people. The peace with Israel has little support among the populace. It’s not just that Israel is not loved, it’s that Jews are hated.

Think back to Sadat writing his pretend letter to Hitler. This was eight years after the ovens of Auschwitz were demolished and much of the world was coming to grips with the enormity of the Holocaust. Yet not only could an Egyptian magazine solicit such letters, but an army officer with the intellectual wherewithal to someday run the country was an entrant. This suggests a society in which the Holocaust was thought to be either a Jewish concoction, a Jewish exaggeration or some sort of just deserts.

Since those days, the situation has evolved but not necessarily improved. Egyptian society, indeed the entire Arab world, has been drenched by a steady drizzle of government-approved or -tolerated anti-Semitism. It would take willful historical ignorance to dismiss the possible consequences. There are almost no Jews left in Egypt — the substantial community was expelled, first by Gamal Abdel Nasser and then by incessant oppression and fear — but there are plenty of Jews just over the border in Israel.

The clock must move backward for the United States as well. It took Harry Truman just 11 minutes to recognize the new State of Israel in 1948 — and he did so over the vociferous objection of some key aides, particularly the immensely important Gen. George C. Marshall, the secretary of state. As the historian and Israeli Ambassador Michael B. Oren writes in his book “Power, Faith and Fantasy,” Marshall felt so strongly that he told Truman to his face that if he recognized Israel, “I would vote against the president.” Truman didn’t blink.

Marshall’s arguments are not entirely invalid. The Arab world has the oil, the geography and the numbers. But the United States has the moral obligation to stick by the sometimes obstreperous democracy it felt morally obligated to embrace. The Obama administration has to show no daylight between it and Israel — never mind that Benjamin Netanyahu is no Ben-Gurion.

Leaders come and leaders go, but what remains are values and cultural forces that transform glacially. Sadat proved this. He was a confounding character who showed what is possible and what is not. He was hope and he was despair and, finally, he was tragedy. It’s clear he changed greatly over the years. It’s not so clear his country has.