An outbreak of COVID-19 tore through Washington in the first week of October, reaching all the way up to the president. With a skeleton crew operating out of the White House, multiple politicians, White House staff, and members of the press in quarantine, and an unclear prognosis for just how far-reaching and this outbreak will get, theoretical discussions have bubbled up about the presidential line of succession—and whether those in that line ought to be quarantining out of an abundance of caution.

The framers of the Constitution provided the solution for the what-if scenario in Article 2, Section 1, establishing a line of succession that has been triggered just nine times in history. Although the line of succession falls to 18 people, it has only ever extended as far as the vice president, who is first in line to succeed the president. In total, eight vice presidents have assumed the presidency after the death of a president, while Gerald Ford remains the only vice president to become president following a resignation from office. In 1985, Vice President George H.W. Bush was president for just eight hours while President Ronald Reagan underwent surgery.

Members of Congress and of the president's cabinet are also in the line of succession, but are only eligible for the job if they meet the requirements for the presidency, which stipulate that a person must be at least 35 years old, a natural-born citizen, and a resident of the United States for at least 14 years.

U.S. law considers almost every worst-case scenario, providing for a designated survivor during the president's annual State of the Union address in case calamity were to strike Capitol Hill, and even figuring out what would happen if the president-elect were to die before officially taking office.

Read on to find out who is currently in line to take over as president, and the often-forgotten history behind the particular order.

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Article 2 of the U.S. Constitution establishes that if the sitting president is removed from office upon death, resignation, or the inability to serve, the vice president would assume the role of president. Nine vice presidents have ultimately taken on the role of president after a president's death or removal from office, but there wasn't a process for selecting a new vice president under this circumstance until the 25th Amendment was ratified in 1967. Vice President Mike Pence is currently first in line for the presidency if President Donald Trump were to leave office.

The 1792 Presidential Succession Act placed the speaker of the house further behind in the line of presidential succession, and the 1886 Presidential Succession Act removed both the speaker of the house and the president pro tempore of the Senate from the line of succession entirely. However, after Harry Truman assumed the presidency following Franklin Roosevelt's death in 1945, he argued that elected officials should be higher in the line than appointed cabinet officials, and a new law was adopted in 1947. Nancy Pelosi, the current speaker of the house, is the only Democrat in the line of presidential succession.

Historically, the Senate has elected the most senior member of the majority party as president pro tempore of the Senate, who is charged with presiding over the legislative body in the absence of the vice president. Similar to the speaker of the house, the president pro tempore was removed from the line of succession in 1886, only to be reinstated in 1947. President Harry Truman's decision to put the speaker of the house before the president pro tempore in the line of succession could be due to his friendship at the time with the speaker. The current president pro tempore of the Senate is Sen. Chuck Grassley, R-Iowa.

Before 1947, the secretary of state was second in line to the presidency after the vice president. One of President Harry Truman's rationales for changing the order of succession was to block a president from being able to handpick his or her own successor, which they could do with the appointment of any cabinet position. If the president were to resign from office—which has only happened once, in the case of Richard Nixon in 1974—the president is required to submit his resignation to the secretary of state. The current secretary of state is Mike Pompeo.

The order of presidential succession after the vice president and senior members of Congress falls to the president's cabinet members in the order the positions were created. The secretary of the treasury was one of the first positions to be established, with Alexander Hamilton serving as the country's first treasury secretary. Today, Steven Mnuchin is secretary of the treasury, and fifth in line for the presidency.

Mark Esper became acting secretary of defense on July 23, 2019. While the secretary of defense is sixth in line for the presidency, it is unclear whether acting cabinet officials are eligible to serve in the line of presidential succession. A number of scholars interpret the Presidential Succession Act to mean that acting cabinet secretaries are eligible for succession so long as they have previously been confirmed by the Senate for a secondary position in their current department, but this point is often disputed, and would likely create a slew of legal challenges if the situation arose.

Attorney General William Barr is responsible for representing the United States in legal matters and offering legal advice to the president, as well as to cabinet officials. The position was created with the passage of the Judiciary Act in 1789, and the attorney general became the head of the Department of Justice in 1870. As attorney general, Barr also oversees the FBI, Drug Enforcement Administration, and the Bureau of Alcohol, Tobacco, Firearms, and Explosives.

Similar to Defense Secretary Patrick Shanahan, the current secretary of the interior—David Bernhardt—holds the position in an acting capacity, meaning that his place in the presidential line of succession is unclear. Bernhardt assumed the role after former Interior Secretary Ryan Zinke resigned on Jan. 2, 2019. However, President Trump has nominated Bernhardt to serve as permanent secretary of the interior, and confirmation by the Senate would cement his place in the line of presidential succession.

The Department of Agriculture was established in 1862 by President Abraham Lincoln. Sonny Perdue, the current secretary of agriculture, is the 31st person to serve in the role, which is responsible for promoting agriculture production and providing economic opportunities for rural America. Perdue brings his experience as a former farmer to the position, but he was also a state legislator and governor of Georgia.

As the current secretary of commerce, Wilbur Ross is in charge of promoting job creation and economic growth through the enforcement of fair and reciprocal trade. Similar to President Trump, Ross is known for his being a wealthy businessman, and built his career by investing in bankrupt companies in the steel, textile, financial, and auto industries. Ross has also been plagued by a series of scandals during his tenure as commerce secretary, including a 2017 investigation by Forbes magazine, which found that he inflated his net worth to be included in the publication's list of wealthiest people.