The most examples of successful racial integration I know are in religious communities. Jews of different races get along fairly well, though they still divide along the lines of Ashkenazi, Persian, Sephardic and may have very little to do with each other, but at least Jews rarely murder each other.
When Ashkenazim and Sephardim are forced to mix in certain rituals, they often end up resenting the influence of the other on their traditional way of doing things.
I grew up a Seventh-Day Adventist, and SDAs are racially diverse. Still, the races didn’t mix much. Virtually all the SDA intellectuals were white. There were white Adventist churches and Korean Adventist churches and in some churches where whites and blacks worshipped together, they sat on different sides. Growing up, I heard a story about a liberal young white woman who deliberately sat with the blacks. They told her, “You think we stink and we think you stink, so go sit with your own.” That story made an impression on me. Even though I knew Adventists of very race, I noticed that they still stayed mainly with their own kind.
Most people I’ve known in a racially mixed marriage told me that it makes things much tougher and very few of them recommend it to me. For instance, I have a thing for Persians, but Ashkenazim who’ve married Persians normally counsel me against it. The most harmonious racially-mixed marriages I’ve seen were white guys with asian women.
Seventh-Day Adventist Tutsis committed genocide against Hutus (SDA and otherwise) in Rwanda in 1994, but I don’t like to think about that because it makes me uncomfortable. The New York Times reported in 2003:
A Protestant clergyman and his son, a physician, were convicted yesterday of genocide and sentenced to prison by the United Nations tribunal dealing with the Rwandan killing frenzy of 1994, in which members of Hutu gangs killed an estimated 800,000 minority Tutsi and moderate Hutu over three months.
The Rev. Elizaphan Ntakirutimana, 78, the former head of the Seventh-day Adventist Church in western Rwanda, was sentenced to 10 years in prison for aiding and abetting genocide. His son, Dr. Gérard Ntakirutimana, 45, who worked at the church’s hospital, received a total sentence of 25 years for the same charges and for shooting two people to death.
With the verdict, Mr. Ntakirutimana became the first clergyman to be convicted of genocide by an international tribunal.
The lengthy trial, which began in September 2001, has drawn new attention to the role of the Christian churches during the massacre. Three Roman Catholic priests are being held on similar charges at the tribunal’s jail in Arusha, Tanzania, the seat of the United Nations tribunal on Rwanda. A fifth, an Anglican bishop, died while in detention.