Patricia Lynn Murray is an American politician who has served as president pro tempore of the United States Senate since 2023 and the senior United States Senator from Washington since 1993. A member of the Democratic Party, Murray served in the Washington State Senate from 1989 to 1993. She was Washington's first female U.S. senator and is the first woman in American history to hold the position of president pro tempore. Murray is also the youngest senator to occupy the office of president pro tempore in more than five decades. As president pro tempore, Murray is third in the line of succession to the U.S. presidency.

The Democratic Caucus of the United States Senate, sometimes referred to as the Democratic Conference, is the formal organization of all senators who are part of the Democratic Party in the United States Senate. For the makeup of the 118th Congress, the caucus additionally includes three independent senators who caucus with the Democrats, bringing the current total to 51 members. The central organizational front for Democrats in the Senate, its primary function is communicating the party's message to all of its members under a single banner. The present chair of the Senate Democratic Caucus is Chuck Schumer of New York.