The Biden Administration will name its designated survivor ahead of Tuesday’s State of the Union address. The designated survivor, or cabinet member not in attendance, is the person who will become president should everybody in the line of succession be killed.
White House administrations don’t use designated survivors frequently, but they are used for inaugurations and Joint Sessions of Congress, like the State of the Union address.
The practice goes back to the early 1960‘s, when lawmakers became fearful of nuclear attacks during the Cold War.