Analysts frequently argue that ethnic conflict in general, and separatism in particular, is contagious. This article develops the logic of diffusion and then considers the role potentially played by domestic political dynamics. The article then tests external and internal dynamics by applying logistic regressions to the Minorities at Risk Dataset. We find that while domestic factors perform somewhat better by themselves, when combined into one model, each argument helps to explain why some groups seek separation while others do not.
Nationalism and Ethnic Politics

Ayres, R.W. (R. William), & Saideman, S.M. (2000). Is separatism as contagious as the common cold or as cancer? Testing international and domestic explanations. Nationalism and Ethnic Politics, 6(3), 91–113. doi:10.1080/13537110008428605