Let's hope it never happens. But the precedent is there, a part of recent history, for the possibility that our president might at some point need to be replaced.
Come November, either Barack Obama will be re-elected as the president of the United States, or presumed-nominee Mitt Romney will be elected for a first term presidential role.
Their successors, if it came down to it, would be either Joe Biden or Paul Ryan.
President Joe Biden. President Paul Ryan. How do those monikers sound to you?
If you've been around long enough, you remember Vice President Lyndon Baines Johnson, stepping in for then-President John Kennedy when in 1963 Kennedy was assassinated in Dallas. And you certainly remember - or at least you've heard about - Vice President Gerald Ford taking the reins from then-President Richard Nixon in 1974 after the Watergate scandal brought Nixon's career to an end.
Anything can happen, and our American Constitution states the vice president is the first person to take command if the need arises.
This week, for the first time in the presidential campaign, we had some real focus on the vice presidency, often a position relegated to page three of the newspaper, to the second block of the newscast.
Mitt Romney named Ryan, a U.S. Representative from Wisconsin, as his running mate. The weekend choice was the top story for several days on many media outlets.
Though young, Ryan is a Washington, D.C. veteran of politics, serving his home state for nearly 13 years. Elected at the age of 29, Ryan is chair of the powerful House Budget Committee. At a time when the economy ranks as the number one issue of concern in our country, Ryan has proposed privatizing Social Security, and replacing Medicare with a voucher program for those now under 55.
Meanwhile, Biden made headlines with some controversial comments at a speech in Virginia, as he told supporters the Republican presidential candidates and GOP lawmakers would put them "back in chains." Hundreds of black people were in attendance for the speech.
President Obama felt the need to defend Biden, saying the vice president's remarks referred to what would happen if Republicans succeeded in getting rid of restraints on financial institutions.
As vice president, Biden held the oversight role for infrastructure spending from the Obama economic stimulus package. He also negotiated bipartisan deals with Congress that resulted in the Tax Relief Act of 2010.
Both men have strong credentials. Both have strong ties to the economy, yet look in different directions in moving forward.
If it happened, if one was suddenly swept into the role of the presidency, with whom would you feel a greater comfort level? If Paul Ryan or Joe Biden became the president, who would be the better choice?
Let us know in your comments. Then vote in our poll below.