The main reason that the West Bank became occupied by Israel in 1967 is because the West Bank was occupied by Jordan and Israel was a constant target. After the 1967 war, the consequence is that the West Bank will never again be used as a staging ground to attack Israel again.
A little history — During Jordan’s two decades of occupation of the West Bank, it was the only time in history that Jews were forbidden from settling in the West Bank. Arabs were given full Jordanian citizenship. The Jordanians immediately expelled all the Jewish residents of East Jerusalem. All but one of the 35 synagogues in the Old City were destroyed over the course of the next 19 years, either razed or used as stables and chicken coops. Many other historic and religiously significant buildings were replaced. The ancient Jewish cemetery on Mount of Olives was desecrated, and the tombstones were used for construction, paving roads and lining latrines; the highway to the Intercontinental Hotel was built on top of the site.—In the mean time, Arabs in Israel were given full citizenship.