The saying “the buck stops here” is used to refer to the person who takes responsibility. It is derived from the expression “pass the buck” which means to pass responsibility from one person to another.
The phrase “pass the buck” comes from the game of poker, in which a marker, called a buck, was used to indicate the dealer. When changing dealers, the first dealer would “pass the buck” to the new one, thus passing responsibility.
During his presidency, Harry Truman kept a sign on his desk, which read “The Buck Stops Here.” It was his way of showing that, as the leader of the United States, he was responsible for anything that happened in the nation.
He also made several references to this quote during his public statements, and in his farewell address, President Truman said “The President – whoever he is – has to decide. He can’t pass the buck to anybody. No one else can do the deciding for him. That’s his job.”