Treasury Secretary Janet Yellen would become president of the United States in the case of a hypothetical Capitol disaster since President Biden has not named a "designated survivor" for his Wednesday address to Congress.

A designated survivor is the person in the presidential line of succession chosen not to attend an event in the case of a mass casualty event that kills all other potential successors; designated survivors typically stay in an undisclosed location during important events.

BIDEN SAYS NO MASKS OUTDOORS FOR FULLY VACCINATED PEOPLE STEP TOWARD 'NORMAL LIVING'

"There does not need to be a designated survivor because the Cabinet will be watching from their offices or their homes," White House press secretary Jen Psaki said during a Tuesday briefing when asked whether the president would have a designated survivor during Wednesday's speech in light of COVID-19 audience restrictions keeping some Cabinet members home.

The White House clarified to Fox News that because of the White House's decision, Yellen would take over as president in the case of a catastrophe unless Democratic Vermont Sen. Patrick Leahy, Senate president pro-tempore, decides not to attend the event in person, in which case he would fall next in the line of succession.

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Yellen is the defacto-designated survivor in this case because the No. 1 successor, Secretary of State Antony Blinken, will be in attendance at Biden's speech on Wednesday.

The president will be delivering an address Wednesday before a joint session of Congress at 9 p.m. EST.