There is no necessary logical connection between religious pluralism and religious freedom. In theory, there could be a nation in which some one religious tradition is dominant and officially established, while members of minority religious groups are perfectly free to worship and witness according to their own convictions. In practice, however, religious freedom has usually arisen out of religious pluralism and conflict. When Professor John Figgis aphoristically remarked that political liberty is the residuary legatee of ecclesiastical animosities, he expressed one half of the truth. The other half is that the churches have sometimes embraced religious freedom out of friendship and as a matter of principle, as something flowing from the Gospel. In 1960, the Faith and Order Commission of the World Council of Churches composed a landmark statement on Christian Witness, Proselytism, and Religious Liberty. Several years later, the Second Vatican Council issued its own Declaration on Religious Freedom. The task of composing this document was significantly assigned to the Secretariat for Promoting Christian Unity, which was also charged with fostering better relations with Judaism. Progress in ecumenism and interfaith relations was seen to depend on religious tolerance and freedom.
Avery Cardinal Dulles, "Religious Freedom and Pluralism," Journal of Markets & Morality 5, no. 1 (Spring 2002): 169-182