Why do major powers intervene in some regime conflicts but not in others? Why do major powers sometimes back the incumbent regime, but other times support the regime challengers? This paper introduces the concept of regime conflicts as watershed moments for countries undergoing organized challenges to the status quo and asks when major powers intervene in these conflicts to tip the balance of power toward revolution or, alternatively, to shore up the incumbent regime. Using a disaggregated dataset of regime conflicts from 1990 to 2013, we analyze the extent to which humanitarian concerns, preservation of the status quo, and major power competition influence the likelihood of major power intervention, and also examine whether, and if so how, democratic major powers may behave differently from non-democratic ones. The analysis shows that democratic major powers do indeed appear to be motivated by humanitarian concerns, whereas non-democratic major powers are not in a systematic manner. We further find that democratic major powers are more likely to promote than to defend democracy, while the reverse applies to autocratic major powers, which are more likely to defend non-democratic incumbents than to promote autocratic challengers. We discuss the interpretation and limitations of these results, and then conclude with implications and directions for future research.
