The South African Defense Force (SADF) is the military of the Republic of South Africa which succeeded the Union Defense Force (UDF) in 1957, shortly before South Africa became a republic. The Defense Act (44 of 1957) established the SADF and continues to serve as its primary legislative framework. The primary role of the Defense Force is dualistic - it must firstly serve as a conventional military force to defend the Republic, its territory and interests; and must secondly act as a counterinsurgency force, which is usually in support of the Security Branch. The Defense Force and the Security Branch complement one another in the overall national security of South Africa and are usually considered to be entwined in terms of functions, staff and role.