An executive order in the U.S. provides the president with the authority to direct the operations of the federal government without needing congressional approval. This power enables the president to implement policy changes quickly and address urgent issues. However, executive orders are limited in their scope and can be challenged in court or revoked by future presidents. They allow for swift action but can also raise concerns about the concentration of power and the potential bypassing of democratic processes, reinforcing the importance of checks and balances in governance.