Separation of Church and State would do exactly the opposite; it would create animosity towards other cultures. This separation would be seen by many people, including extremist groups, as pandering to non-Christian religions and cultures in an attempt to show a greater level of acceptance.  This would result in people blaming non-Christian religious groups and cultures for the changes and giving ammunition to extremist groups who wish to incite racism. Rather than benefitting immigrants and people who follow non-Christian religions, this would actively harm them. [1]  [1] Iannaccone, Laurence R. “Religious extremism: Origins and consequences” Contemporary Jewry. Volume 20. 1996.