Malaysia is a federal constitutional monarchy. It has a parliamentary system of government selected through periodic, multi-party elections and headed by a prime minister. The king is the head of state and serves a largely ceremonial role; the kingship rotates among the nine sultans every five years. The United Malays National Organization (UMNO), together with a coalition of political parties known as the National Front (BN), has held power since independence in 1957. On May 5, in general elections, the BN was re-elected although it lost the popular vote to the opposition coalition. The opposition and civil society organizations alleged electoral irregularities. Civilian authorities failed at times to maintain effective control over security forces. Security forces committed human rights abuses. The most significant human rights problems included obstacles preventing opposition parties from competing on equal terms with the ruling coalition; restrictions on freedoms of speech, assembly, association, and religion; and restrictions on freedom of the press, including media bias, book banning, censorship, and the denial of printing permits. Other human rights problems included deaths during police apprehension and while in police custody; the persistence of laws that allow detention without trial; caning as a form of punishment imposed by criminal and sharia courts; bans on religious groups; restrictions on proselytizing and on the freedom to change one's religion; official corruption; violence and discrimination against women; discrimination against lesbian, gay, bisexual, and transgender (LGBT) persons; and restrictions on the rights of migrants, including migrant workers, refugees, and victims of human trafficking. Longstanding government policies gave preferences to ethnic Malays in many areas. The government restricted union and collective-bargaining activity, and government policies created vulnerabilities and worsened child labor and forced labor problems, especially for migrant workers.