Today is the 40th anniversary of the Six Day War, which broke out on June 5, 1967 and ended less than a week later with a spectacular Israeli victory over the combined forces of Egypt, Syria, and Jordan that changed the map of the Middle East.

And yet it’s a curious thing: Although the map that was changed had been in existence for less than 20 years, starting with Israel’s war of independence between 1948 and 1949, and more than twice as many years have gone by since then, it continues to be regarded by the world as the “right” map while the map that replaced it is considered a temporary aberration that needs to be canceled or reversed.

The same holds true for many Israelis’ view of their own country. Particularly on the Israeli Left, one still hears pre-1967 Israel spoken of as the “real” Israel that should be longed for and returned to — an Israel of supposed democratic values, humanistic principles, and equal rights as opposed to the occupying power of the past four decades.

Yet only those who have had 40 years in which to forget could romanticize the past in this way.

Although it was not in occupation of the West Bank, the Gaza Strip, or the Golan Heights, the Israel of the years before 1967 was in many ways, not a more, but a less democratic society than it is today.

There was far less economic freedom, less freedom of speech, and less freedom of religion; military censorship of the press still existed. Israel’s Arab citizens, in some ways, were treated no better than how the Palestinians of the occupied territories are today.

Not many people may remember it, but from 1948 until shortly before the Six Day War, most of Israel’s Arabs, though they had the right to vote, were subject to military rule and could not even travel freely from place to place without a permit.

Similarly, the world has forgotten what the pre-1967 map was really like. Far from being demarcated by clear and accepted borders, it showed Israel separated from Egypt, Jordan, Syria, and Lebanon by mere armistice lines, frontiers created by the ceasefire that ended the 1948-1949 war and considered temporary by all Arab countries, not one of which recognized Israel and all of which looked forward openly to its destruction — an easily imaginable eventuality in view of the fact that these frontiers narrowed to a few miles’ width along the Mediterranean coastal plain where Israel’s population was most concentrated.

In the meantime, Israel’s Arab neighbors sealed them off as if they were not borders but prison walls, refusing to let Israelis cross them for any purpose while letting armed fedayeen foray into Israel to kill and commit acts of terror.

Nor did the rest of the world necessarily consider these frontiers permanent, either. In the early 1950s, for example, the foreign minister of Britain, Anthony Eden, hatched a plan, seriously weighed by the U.S. secretary of state, John Foster Dulles, according to which Israel would cede a large part of its southern Negev — territory entirely within the 1948 armistice lines — to Egypt in order to give the latter territorial contiguity with Jordan and the eastern half of the Arab world.

Such were the “good old days” before the Six Day War broke out — a war, today widely considered to be the root of all the evil in today’s Middle East, that the weak of memory now assume must have been Israel’s fault, since who can believe that the Arabs chose to provoke an armed conflict in which they were routed from tens of thousands of square kilometers of territory within a few days?

Who? Well, for starters, anyone who was actually alive in 1967 and hasn’t joined in, or been brainwashed by, the rewriting of history that has taken place since then.

You don’t have to have total recall to recollect that the 1967 crisis began when Egypt sent its troops into what was supposed to be a demilitarized Sinai, out of which it booted a U.N. policing force, and imposed a naval blockade on the Israeli port of Eilat; that as the crisis escalated, Arab mobs took to the streets everywhere, screaming for Israel’s immediate annihilation; that Israel’s political leadership, desperate to avoid a war it didn’t want, begged the international community to find a solution while refusing to heed its generals’ demand for a preventive strike; and that even after this strike took place in the form of the demolition of Egypt’s air force and the blitzkrieg in Sinai, the war spread to Israel’s eastern and northern fronts only after Jordan and Syria opened fire on Israel first.

It is amazing how little of this is now remembered, just as it is no longer remembered that immediately after the June 1967 war, Israel was ready to return nearly all of the land conquered by it in return for peace and was answered by a monolithic Arab refusal to negotiate, accompanied by a partial recommencement of hostilities by Egypt in the so-called 1968-1970 “War of Attrition” — a war that has also disappeared from the world’s consciousness amid the general amnesia.

History, it is said, is written by the winners, but the history of the 1967 war and what came before it has been so successfully written by the losers that the winners’ account is scoffed at incredulously today even by supposedly knowledgeable people. Forty years after it took place, the world has gone steadily backwards in its understanding of how and why it did.

Mr. Halkin is a contributing editor of The New York Sun.