There is an enormous amount of research about conflicts and polarisation, like the Allport contact hypothesis and also the genocide literature of Abram de Swaan. What lacks to my opinion is research about how to end a conflict effectively. Possible parties who might intervene are victims, offenders and bystanders. Much of the work I know about ending conflicts like colonisation, suppressing people by means of racism etc. is based on Martin Luther King, the Dalai Lama, Nelson Mandela and Mahatma Gandhi.