Israel's Borders

Consider President Obama’s latest proposal: Israel should return to the 1966 borders. How is this suggestion not arbitrary? I mean, could not the Prime Minister of Israel counter with this equally valid proposal: Israel should return to the 966 BC borders? In fact, the American Indian nations should take this opportunity to step up to the plate with their own proposal: North America should return to the 1566 borders. What is the difference between the “Six Day War” and any other war in which one side got its butt kicked by the other side?