Thailand is a constitutional monarchy. The King serves as head of state and has traditionally exerted strong influence. A coalition government led by Prime Minister Yingluck Shinawatra and her Puea Thai (For Thais) Party came to power in 2011 following National Assembly lower house elections that were generally viewed as free and fair. Authorities maintained effective control over the security forces. However, some members of the security forces were involved in human rights abuses. The most persistent human rights problems included: abuses by government security forces and local defense volunteers in the context of the continuing Malay-Muslim separatist insurgency in the three southernmost provinces; occasional excessive use of force by security forces, including police killing, torturing, and otherwise abusing criminal suspects, detainees, and prisoners; and continued government limits on freedom of speech and press. Other human rights problems included: occasional arbitrary arrests and detention; continued poor, overcrowded, and unsanitary prison and detention facilities; government limits on freedom of assembly; insufficient protection for vulnerable populations, including refugees; violence and discrimination against women; sex tourism; sexual exploitation of children; trafficking in persons; discrimination against persons with disabilities, minorities, hill tribe members, and foreign migrant workers; child labor; and some limitations on worker rights. Authorities occasionally dismissed, arrested, prosecuted, and convicted security force members who committed abusive behavior. Official impunity, however, continued to be a serious problem, especially in provinces where the 2005 Emergency Decree, the 2008 Internal Security Act, and martial law remained invoked.