As Iran continues to insist all the sanctions must be lifted immediately if it complies with a new framework for a deal, the President and his negotiating team are scrambling to incorporate this requirement into the final negotiations. They are taking a logical approach by asking themselves the reason for a phased lifting of sanctions and whether it can be achieved in some other way.
The idea of a snap-back of sanctions should Iran be caught cheating on the deal seems to be the most promising approach. Easy re-imposition of the sanctions could take the place of a phased lifting while still giving Iran the possibility of asserting they made a good deal. Whether Iran or Secretary Kerry was misinterpreting the framework is irrelevant provided a deal is reached.
The new need for Congressional approval looms over the negotiations like a sword of Damocles. Whether the Senate has the gumption to reject an executive agreement with another
nation remains to be seen, but there are certain prerogatives for the President that are still honored. For example, the Senate will eventually confirm Loretta Lynch as the new Attorney General despite all the unnecessary fuss about immigration and unrelated legislation.
Despite all the ado, I think the President will persist and achieve an agreement with Iran, including the lifting of sanctions by the Congress. Because the alternative is war, and the Republican Party desperately wishes to avoid that.