Head of state second and last incumbent of the office, Yusof bin Ishak, kept the style at 31 August 1963 unilateral declaration of independence and after 16 September 1963 accession to Malaysia as a state (so now as a constituent part of the federation, a non-sovereign level). After its expulsion from Malaysia on 9 August 1965, Singapore became a sovereign Commonwealth republic and installed Yusof bin Ishak as its first President. In 1959 after the resignation of Vice President of Indonesia Mohammad Hatta, President Sukarno abolished the position and title of vice president, assuming the positions of Prime Minister and Head of Cabinet.
Federation independence from the sovereign state, which only takes care of their foreign relations and defence. However, they are neither considered to be part of it, nor recognised as sovereign or associated states. The distinction between a federation and a unitary state is often quite ambiguous. A unitary state may closely resemble a federation in structure and, while a central government may possess the theoretical right to revoke the autonomy of a self-governing region, it may be politically difficult for it to do so in practice. The self-governing regions of some unitary states also often enjoy greater autonomy than those of