Which of the following powers is expressly granted to the President by the Constitution?

The power to execute laws is expressly granted to the President by the Constitution in Article II, Section 3, which states that the President "shall take Care that the Laws be faithfully executed." This emphasizes the President’s role as the chief executive officer, responsible for ensuring that federal laws are implemented and enforced. This power includes overseeing the various federal agencies and departments, appointing officials, and directing the overall administration of federal laws.

In contrast, the other choices do not assign powers directly to the President. The power to declare war is primarily vested in Congress, as outlined in Article I, Section 8 of the Constitution. The power to write laws also belongs to Congress, as the legislative branch is responsible for creating statutes. Lastly, amending the Constitution requires a process that involves either a two-thirds majority in both houses of Congress or a convention called by two-thirds of state legislatures, and therefore is not a power granted to the President.