A certain Oval Office-centric show is about to return to TV for a second season, so knowing how a designated survivor works in real life seems key. In Designated Survivor Season 1, Kiefer Sutherland as Secretary of Housing and Urban Development Tom Kirkman gets told that, after an explosion in the Capitol building, given the sheer number of lives that have been taken, he becomes president by default. Obviously, this is a nifty plot device, taking him from being a schlubby politician who's just been offered a demotion to the biggest deal in politics in the course of a single day. But does it work like that in real life, too?
Actually, yes. According to CBS News, the position is a result of the Presidential Succession Act of 1947, which aimed to create a logical sequence of succession in case of the president dying or becoming incapacitated. The sequence goes Vice President, then Speaker of the U.S. House, then the President Pro Tempore of the U.S. Senate. After that, according to ABC News, the office then passes to,
"...the secretaries of state, treasury, and defense, the attorney general, and the secretaries of the interior, agriculture, commerce, labor, health and human services, housing and urban development, transportation, energy, education, veterans affairs and homeland security."
However, this line of succession doesn’t work if all of these important folks assemble in one place all at once, as they’re expected to occasionally do, like, for example, at the State of the Union address. And that’s why there’s a designated survivor. This person is selected from the members of the Cabinet so that, if there was a big attack on the Capitol (as in the show), there’d be someone around to be sure that the current government could stay in power.
According to Obama's speechwriter Jon Favreau, who spoke to The Ringer, the designated survivor isn't randomly chosen. The choice may depend on something like whether their programs or areas of policy will be discussed in the State of the Union, citing years when it was widely known that education would be a focal point "and therefore Arne Duncan, who was the education secretary at the time, could not be the designated survivor." This actually lines up with the show, where it's stressed that Kirkman's policy suggestions don't form part of the President's speech, and, as such, it's unnecessary for him to swing by the State of the Union address.
It should also be stressed that not just anyone can take the role. According to The Washington Post, the candidate for designated survivor must fit the same criteria as the President does; they must be at least 35 years old and a natural-born citizen, which, as the same paper comments, would rule out Cabinet members not born in the U.S. Thus, for example, Donald Trump's Secretary of Transportation, Elaine Chao, wouldn't be able to fill the role since, according to the Huffington Post, she was born in Taiwan.
But what does taking the role actually involve? In a 2007 CBS article on what it's really like to be a designated survivor, they report that Attorney General Alberto Gonzales, who was chosen to take the role that year, had to keep his location secret. They also spoke to Secretary of Agriculture to President Clinton, Dan Glickman, who performed the role in 1997. He explained that the U.S. Secret Service advised him to leave Washington D.C. for the evening, so he visited family in New York. And he said that he was not given a briefing on what to do if something had happened.
So, yes, this is a very real role — and one that's only getting more significant in a time of increased national security. The Washington Post revealed in September 2016 that, for the past decade, there'd been not one, but two designated survivors. One of these would reconstruct the executive branch while the other would "lead a new legislature," apparently. They also cite a brusque "no comment" on the part of more recent cabinet members who have taken the role, suggesting the innate secrecy involved taking the position is more significant than ever.
Thank goodness that what happens in Designated Survivor is only the plot of a TV show, but, as the growing emphasis on the real life role suggests, the possibility of an attack on the Capitol building is being taken as exactly that: possibility, not fiction.