Rejection of the Iran deal would allow a period of 9-10 months to strengthen our options
The key point is that a “no” vote on the Iran deal has little practical impact until next year. Between now and then, such a vote buys time, adding up to nine months to the strategic clock. If, before the vote, Obama refuses to adopt a comprehensive set of remedial measures that improves the deal, then a resounding vote of disapproval gives the president additional time to take such action and then ask Congress to endorse his new-and-improved proposal.
Chastened by a stinging congressional defeat in September—one that would include a powerful rebuke by substantial members of his own party—the president might be more willing to correct the flaws in the deal than he is today. That would surely be a more responsible and statesmanlike approach than purposefully circumventing the will of Congress through executive action that effectively lifts sanctions—an alternative the president might consider if he is hell-bent on implementing the agreement.