The position of those opposing the deal was that because it was not a treaty, it was not binding and a future President could revoke the agreement. Back in September, liberal law professors Bruce Ackerman and David Golove took Senator Marco Rubio to task in The Atlantic for making this claim, stating flatly, "Rubio is wrong". Their view was that this is a Congressional approved Executive Agreement and thus the Senator's position was nothing more than:
an unprecedented pledge to inaugurate his term by repudiating the constitutional command to “take care that the laws be faithfully executed.” There has already been too much lawlessness from the presidency since September 11th; Rubio’s celebratory anticipation of further illegalities represents a new low.What irresponsible ignorance from the Senator! We are shocked!
Of course, one thing to keep in mind about any statements from law professors about the state of the law is that they are very prone to describing the current state of the law according to what they think it ought to be rather than what it is. Since the legal academy leans left most such assertions lean in that direction (see for instance, the embarrassing performance of law professors when predicting outcome of the commerce clause arguments around the Affordable Care Act).
Thankfully, the matter has now been clarified and the Obama Administration has made it clear it agrees with Senator Rubio and not with the distinguished professors. In response to a letter from Representative Mike Pompeo (R-KS) regarding the status of the Joint Comprehensive Plan of Action (JCPOA) or "the deal" in which he noted that none of the parties to the JCPOA had actually signed it, the State Department responded on November 19 stating that the JCPOA is:
Not a treatyAccording to the State Department the JCPOA is merely a "political commitment".
Not an Executive Agreement
Not a signed document
Not legally binding
We are not making this up, read it for yourself.