Madrid-based Prisoners Defenders, an NGO focused on Cuban human rights, reported that the Cuban and Russian governments signed an agreement in which Cuba would send soldiers to join the war in Ukraine. Such a development raises many important questions. The Wagner Group’s dramatic failed mutiny displayed something the Kremlin knew long ago: the group, including its leader, Yevgeny Prighozin, has become a problem for Russia, particularly on the Ukrainian front. The group had little military training and served as cannon fodder in the war. Thousands of its fighters fell in battle. Wagner was convenient to Russia, as many of its...