What is the maximum number of years a person may serve as president of the United States?

The maximum number of years a person may serve as president of the United States is defined primarily by the 22nd Amendment to the U.S. Constitution. This amendment establishes that an individual can serve a total of two elected terms, which amounts to eight years.

In addition to this, there's a provision that allows someone who has succeeded to the presidency (for example, if a sitting president is unable to complete their term) to serve for up to an additional two years, but this cannot exceed a total of ten years in office. However, for those who are elected to the presidency, the maximum remains two four-year terms, thus reinforcing that eight years is the maximum for an individual serving as president through election.

This provision was established to prevent any one individual from holding too much power for an extended period, promoting a balance in governance and facilitating regular democratic transitions. Therefore, the maximum number of years, accounting for both scenarios, is eight through two full terms.