The Political Bureau (Politburo) is Hamas's main decision-making body whose authority is derived from the support of the Shura Council. The Politburo determines social, political, and military policies, in consultation with the Shura Council.
The Politburo comprises 15 members elected by the Shura Council every four years. It is currently headed by Ismail Haniyeh, who replaced Khaled Mashal in May 2017 following Politburo elections. In practice, though, Yahya Sinwar has assumed effective control over the movement.
In addition to the main Politburo, Hamas has ‘regional’ Politburos elected by four ‘regional’ Shuras, representing the West Bank, Gaza, the diaspora, and prisoners.