What has been less appreciated about Vatican II, though it is as significant as the halting steps on governance, is that it took account of the world outside the church. The church validated for the first time the principle of religious freedom and rejected all forms of civil discrimination based on religious grounds. Thus ended an era of cozy church-state relations that began in the fourth century with Emperor Constantine.
Before the council, Catholics were not only forbidden to pray with those of other faiths but also indoctrinated into a disdain or even contempt for them. (This was, of course, a two-way street.) Now, for the first time, Catholics were encouraged to foster friendly relations with Orthodox and Protestant Christians, as well as Jews and Muslims, and even to pray with them. The council condemned all forms of anti-Semitism and insisted on respect for Judaism and Islam as Abrahamic faiths, like Christianity.
These epochal decisions have been carried out imperfectly, not surprising for an institution as large, lumbering and complex as the Catholic Church….