Currently, international agreements are executed by executive agreement rather than treaties at a rate of 10:1. Despite the relative ease of executive agreements, the President still often chooses to pursue the formal treaty process over an executive agreement in order to gain congressional support on matters that require the Congress to pass implementing legislation or appropriate funds, and those agreements that impose long-term, complex legal obligations on the United States. For example, the deal by the United States, Iran and other countries is not a Treaty.

Answer this question, if possible (if impossible, reply "unanswerable"): What is it about the approval process of executive agreements might lead a US president to prefer them over treaties?
the relative ease