There seems to be something inherent in our human nature (or is it just how we are nurtured?) which demands tribal fealty. The Balkans provides a long existing case study. Many need an "us" and a "them" based upon race, ethnicity, and most often faith group. The good news is how far we weak humans have come. We once warred on one another over what now seem obscure (to the general public) points of theology, killing,  maiming and looting in the process. All in the name of the Prince of Peace. 

Thanks be to God, that is nearly over, even if it's a shaky truce at certain Christian shrines in the Holy Land. Now, Christianity has different challenges, which like it or not tend to place us all in the same lifeboat. An ecumenism of blood in the troubled places. An ecumenism of necessity in western cultures dismissive at best and virulently hostile at worst, to all religion, but mostly Christians. MSW has it right. The work in the world with the downtrodden brings us together. In Jesus name.