I never really thought of this before. The "1967 lines" (which are really the Green line established by the 1949 armistice that ended the Israeli war of independence/Nakba) are still taken seriously, while the 1947 UN partition lines are not, because of a change in international norms that happened to take place between 1949 and 1967.
The 1967 lines themselves were a product of conquest during the 1948-49 war. The post-1967 "greater Israel" that includes Gaza, the West Bank, Golan, and Sinai were also a product of conquest, but those new greater borders never received the degree of international legitimacy and recognition that the 1967 lines did. Israel itself, at least partially, participates in that recognition. For it pulled back to the 1967 lines when it withdrew from Sinai and Gaza, and a modified version of the 1967 lines were used to define the three zones of legal control of the West Bank in the Oslo Accord.
The 1967 lines themselves were a product of conquest during the 1948-49 war. The post-1967 "greater Israel" that includes Gaza, the West Bank, Golan, and Sinai were also a product of conquest, but those new greater borders never received the degree of international legitimacy and recognition that the 1967 lines did. Israel itself, at least partially, participates in that recognition. For it pulled back to the 1967 lines when it withdrew from Sinai and Gaza, and a modified version of the 1967 lines were used to define the three zones of legal control of the West Bank in the Oslo Accord.
