Final answer:
The event on the schedule which is a directly stated constitutional requirement is providing a State of the Union address, as mandated by Section 3 Clause 1 of the U.S. Constitution.
Step-by-step explanation:
Of the events listed, the one that is a directly stated constitutional requirement is providing a State of the Union address. This requirement is found in Section 3 Clause 1 of the United States Constitution, which states that the president must report periodically on the state of the union to Congress. This has evolved into an annual address where the president presents a legislative agenda and policy goals, though it is not binding on Congress.
While delivering remarks at a campaign event, meeting with congressional caucuses, and receiving economic briefings are common presidential activities, they are not explicitly required by the Constitution. In contrast, the State of the Union Address is a specific duty embedded within the presidential role to ensure that the executive branch communicates effectively with the legislative branch.