President Donald Trump's inner circle is said to be facing fears that the biggest threat to his presidency is not impeachment, but rather his cabinet using the 25th Amendment to declare him "unable to discharge the powers and duties of his office."

The amendment has been invoked in this way only three times before, and coincidentally, each time has involved presidential colons.

The 25th Amendment of the Constitution was passed in 1967 after fears about presidential succession after President John F. Kennedy's assassination. The first two sections deal with presidents and vice presidents resigning, dying, or being generally removed from office, and these sections were invoked in order to elevate Gerald R. Ford to the presidency after Richard Nixon resigned in 1974.

The second two sections of the amendment deal specifically with what to do with a president who is unfit to serve, and it is these sections Trump has to worry about. If he is removed under these sections, he would be joining a small list of presidents who all had their powers temporarily removed due to doctors operating on their colons.