The two-party system came to an end under President Ferdinand Marcos, who in 1976 declared martial law. Despite strengthening Communist and Islamic separatist rebellions, Marcos retained firm control of the country until economic issues and disenchantment with corruption led to greater opposition. Opponents consolidated around Corazon Aquino, the widow of an assassinated opposition politician. After Marcos was declared winner of a snap election in 1986, military and public protests led to the People Power Revolution which removed Marcos and installed Aquino. A new constitution increased the limits of Presidential power, including creating a single term limit. Since then, an unstable multi-party system has emerged on the national level, which has been challenged by a series of crises including several attempted coups, a presidential impeachment, and two more public mass movements. This period also saw some political power decentralized to local government, and the establishment of the autonomous Bangsamoro region in Muslim Mindanao.