Final answer:
Presidents use executive agreements as an alternative to treaties to avoid the requirement of Senate approval, but must inform Congress within 60 days due to the Case-Zablocki Act.
Step-by-step explanation:
Executive agreements are often used by presidents as an alternative to treaties, which require Senate approval. However, perceived presidential abuse of this tactic led to the Case-Zablocki Act, which requires that the president inform Congress of an executive agreement within 60 days of its creation.