Identifying Expanding Presidential Powers

The President of the United States is endowed with a set of powers that significantly influence both domestic and foreign policy.

One power, however, stands out in that it is not explicitly defined in the Constitution, leading to various interpretations and applications. This power is often exercised through executive actions, which can sometimes be contentious and lead to judicial challenges.

Which of the following powers best exemplifies this dynamic nature of presidential power that has expanded through practice rather than explicit constitutional wording?