When the Founders drafted the Constitution, they gave the President wide discretion in foreign policy. One the few constraints on presidential power in foreign policy is that treaties can not become law of land unless ratified by two thirds of the Senate. However, even this restriction is of limited meaning if the President can simply call the accord an executive agreement rather than a treaty. The maneuver of making accords by executive agreement rather than treaty has been in existence since the Washington administration. However, the prevalence of that maneuver, as measured by the ratio of executive agreements to treaties, shot up since World War II, and grew considerably more in the most recent administrations.
While Obama has been particularly aggressive in using executive agreements, having a significantly higher ratio of executive agreements to treaties than the next highest administration, the most notable executive agreement is the JCPOA or the Iran deal. The question this creates is what should be done in terms of defining what may be done through executive agreement and what accords should require the President to negotiate a treaty, with the requirement of Senate approval, in order to reach. A few ideas would be to require a treaty for anything involving the release of government-controlled assets or which conflict with existing statutes. Either of those restrictions would have derailed the Iran deal if they had been in effect because the release of frozen assets or the suspension of statutory sanctioned would have triggered a requirement to seek a treaty which would have required affirmative Senate approval to enact rather than simply upholding a veto to prevent its non-enactment. Any other ideas about what should be the division between executive agreement and treaty?