sentences:  Unlike the Shi'ites, the Kurds had a recognized political leadership—the Patriotic Union of Kurdistan (PUK) and the Kurdistan Democratic Party (KDP) that took control of northern Iraq.As a result of this formal political leadership, the revolution in the Kurdish north was much less violent than in the Shi’ite South, and produced relatively few refugees and Internally Displaced Persons (IDPs).In late March 1991, the Bush administration gave the Iraqi government permission to use helicopters against the Kurds.