The wars in former Yugoslavia from 1991–2001, and Ukraine from 2014 to the present, provide revealing examples of the ways in which contemporary armed conflict is evolving. Their origins lay in domestic rather than inter-state disputes, and they emerged as civil wars born of state failure. The belligerent factions were diverse, including established states, new national polities, and radicalized non-state actors. Operationally the wars were liquid conflicts where adversaries, lacking decisive combat power, often shunned conventional military objectives in favor of attacks on populations, terroristic posturing, and symbolic gestures. The conflicts were internationalized, with powerful external actors at odds over responsibility and preferred outcomes. They were European wars, with European and Euro-Atlantic institutions directly engaged in conflict management, peace enforcement, and post-conflict peace building. The conflicts have contributed to the break down of cooperative security in 21st century Europe and the re-opening of an East-West divide running through the heart of the continent. Managing and containing such clashes is and will remain a major strategic challenge.
