I think let him quit. That's the best thing at this hour, because he is more concern of his prestige outside, but is not concern with the negative aspects of the deal. I am not concern of the role Left has to play, but The nuclear deal should be according to our need, not according to their rule. If the PM is so keen to work on the deal, then he should also address the concern in the deal & should be brave enough to explain about the nature of the deal to the people of this country. If that can be done then it's fine, otherwise no need of him continuing as the PM because if he goes, someone better competent than him can occupy the chair & safeguard the interest of our country.