The number of active armed conflicts reached a 25-year peak in 2015, making this another bleak year for international peace and security. These circumstances reinforce the impression that the decline of war, heralded less than a decade ago, is not only halted but reversed. The Uppsala Conflict Data Program (UCDP), the leading provider of statistics on armed conflicts, recorded 50 active cases - those with 25 or more annual battle-related deaths - during 2015. While internationalization of armed conflict in the form of interstate wars has waned since World War II, the number of internal conflicts with international participation has increased steadily over the last 25 years. In the latter part of the 1990s, the extent of international involvement in armed conflicts started to grow. After a nationalist-infused explosion of armed conflicts in the wake of the collapse of communism, the world moved into an exceptionally peaceful period.