The President pro tempore of the California State Senate (President Pro Tem) is the highest-ranking leader and most powerful member of the California State Senate. The officeholder also chairs the Senate Rules Committee. At the beginning of each two-year session, all members of the body elect a new State Senate President pro tempore. The President pro tempore is chosen by the other Senators. The current President pro tempore is Toni Atkins, a Democratic member from the 39th district, who was sworn in on March 21, 2018.