The result has been an the inter-mixing of Jewish and Arab populations in the West Bank and East Jerusalem that renders the achievement of a two-state solution impossible to achieve or indeed even visualize. What the Right calls the "ethnic cleansing" of Jews from the West Bank (and even more so, out of the Greater Jerusalem area) is at this point in time as realizable, concretely and politically, as the ethnic cleansing of Arabs from the West Bank (and East Jerusalem). Hence, the settlement enterprise is a major obstacle to Israeli-Arab and certainly Israeli-Palestinian peace.
Paradoxically, the second major consequence of the Six Day War is that it at last gave Israel "cards" -- that is, chunks of territory -- that it could trade in exchange for peace with the surrounding Arab states. This paved the way for peace with Egypt and, to a degree, peace with Jordan, and to peace talks with Syria. The war also paved the way for Israeli-Arab peace in another way. The decisiveness of the Israeli victory persuaded the surrounding Arab states that Israel was here to stay and could not be eliminated by their armies, and therefore that the Arab world would have to acquiesce in Israel's existence and make its peace with it. At least, this is how the Arab regimes interpreted the war's meaning, and this message was reinforced by Israel's military victory over Egypt and Syria in 1973 (though the Arab masses, never told this simple truth, remained unconvinced, partly due to their leaders' public rhetoric and what is taught in their school systems). Hence, the Arab masses, and especially their academic and professional elites continue to this day to want Israel's destruction or disappearance. Nonetheless, the regimes began to move toward peace - under Sadat in 1970-1971, culminating in the Israel-Egypt peace treaty of 1979 and the Israel-Jordan peace treaty of 1994 and in the Israel-PLO accords, the Oslo accords, and the Israel-Syria peace negotiations of the 1990s.
Seen from 2017 - and it may be a bit early to adequately assess - the Six Day War had two major, historically significant consequences. The first was the emergence in Israel of a Messianic right-wing expansionist movement, epitomized by Gush Emunim (the Bloc of the Faithful), which acted as a vanguard, lobby, pressure group. This movement ultimately prevailed on the Israeli political scene and drove forward an expansionist ethos and the settlement enterprise which embodied and actuated that ethos.
Benny Morris is a professor of history and Middle Eastern Studies at Ben-Gurion University. His publications include One State, Two States: Resolving the Israel/Palestine Conflict (Yale University Press, 2009); Making Israel (University of Michigan Press, 2007); and The Birth of the Palestinian Refugee Problem Revisited (Cambridge University Press, 2004), which received the National Jewish Book Award.