There is a movement in Israel that calls for the extension of Israeli sovereignty over the whole area of Samaria (Shomron) and Judea (Judah) known as the West Bank. There is no question that Israel has the legal right to do this, to annex the West Bank into Israel proper, just at it did for East Jerusalem and the Golan Heights.
These areas were part of the original British Mandate established by the League of Nations in 1920, and ratified by the UN, to establish a Jewish Homeland in Palestine (Britain unilaterally removed the eastern part of Palestine in 1922 and established the Arab State of Jordan). The only sovereign State that replaced the Palestine Mandate was the State of Israel and under international law it therefore inherited the right to all of the territory of the Mandate. There was never in history a Palestinian Arab State with sovereignty in this area.
I have always believed that it was a huge mistake of historic proportions that Israel did not annex these areas when it captured them after the 1967 Six-Day War. It should have done so based on its legitimate legal claim. But, there were two reasons why this was not done: 1. A misplaced belief that by being magnanimous to the defeated Arabs, because of their culture of shame, that they would in return show gratitude. Defense Minister Moshe Dayan also gave them control of the Temple Mount, that was huge error; 2. Because of the demographics, since there were ca. 1 million Arabs in these territories, Israel did not want to include them as citizens. But, it could have been possible to annex the territories without giving citizenship to the inhabitants. Those not wishing to live under Israeli rule would be free to leave (with some financial help).
History is full of examples of countries failing to follow-up on its victories. There was the enormous mistake of Japan not to follow-up the attack on Pearl Harbor in 1941. As Admiral Yamomoto said, “I fear we have woken a sleeping giant.” The Hawaiin Islands were essentially undefended and the West Coast of the US was also without any real form of defense. If the Japanese had captured Hawaii (and the whole US pacific fleet) and then a section of the US coast, before the US had time to react, WWII could have turned out very differently. Here is an example where a country did follow-up; Germany captured and then annexed the province of Schleswig-Holstein from Denmark in 1867. They carried out a plebiscite in 1920, and the majority voted to remain in Germany. That’s how it’s done.
There is a lack of expedient planning in Israel, that tends to take into account the future possible needs of the defeated enemy, rather than its own future possible interests. For example, suppose there is a rise in anti-Semitism in the world (not possible you say?), and a large number of Jewish immigrants suddenly flocked to Israel. Where would she put them? The use of the Jewish territories of Judah and Shomron would make ideal areas of settlement, and it would not require the removal of any of the Arab inhabitants.