What is Section 4 of the 25th Amendment?

As per information published on Congress.gov, Section 4 of the 25th Amendment outlines what should happen if a president becomes unable to carry out their responsibilities but is unable or unwilling to acknowledge it themselves.

The provision was proposed in 1965 before officially becoming law in 1967. In spite of being in place for almost six decades, Section 4 has never been invoked.

By comparison, Section 3 deals with situations where a president voluntarily declares themselves unfit to perform their duties, such as following an unexpected illness or ahead of a planned medical procedure.

Also, Congress.gov notes that this could potentially extend to other circumstances, including a president being outside the country or experiencing an intense period of grief following the death of someone close to them.