There are quite a few, but what concerns me at the moment (and has been for a few years now) is the two-way street between domestic policies and international politics, as well as the impact of technological advances on politics (both domestic and international), and finally the interaction between conflict and individual/group identity.
I’m in the early stages of a research project dealing with the political effects of revolutions in military affairs (RMAs) which are periodically engendered by general technological progress. Even though the revolutions themselves are quite different from one another, tracing the pattern of each revolution and examining the political changes caused by these revolutions would probably go a long way toward understanding systemic forces governing the international system.
I’m also working on a smaller project dealing with leadership style and personality characteristics as an explanation for genocide (this one jointly with my colleague Tracy Slagter), and an almost complete project on a theory of arms transfers and technology proliferation. Plus there are a few projects in the “germination” phase.