But at least one top official is not expected to be in the US Capitol building for Biden’s speech, participating instead in an obscure ritual in order to maintain the line of presidential succession in the rare case that disaster strikes.

Last year, Commerce Secretary Gina Raimondo was the designated survivor for Biden’s first State of the Union address, staying away from the Capitol in an undisclosed and secure location during the president’s prime time remarks.

According to the National Constitution Center, the tradition of a designated survivor during the State of the Union speech began in the 1950s as a result of fears of a nuclear attack during the Cold War.

The updated line of succession was spurred by President Franklin D. Roosevelt’s death in 1945, which led to Harry Truman’s assumption to the highest office.

Data analyzed by CNN shows that the attorney general, seventh in the line of succession, has been the highest-ranking Cabinet member known to have been appointed to be designated survivor.

Acting Cabinet secretaries are eligible for the line of succession if they have been Senate-confirmed for other positions, according to 2003 congressional testimony from John Fortier, executive director of the continuity of government commission.