Congressional Democrats began a coordinated attack last week against the effort to give Congress a say in the nuclear deal with Iran. Sen. Bob Corker (R-TN) has proposed legislation that would make Congress, not the president, the deciding authority on whether or not to relieve sanctions against Iran, since those sanctions were put in place by Congress. Some Democrats are on board with Corker’s plan, but will they hold the line?

Corker has numerous allies on both sides of the aisle, most prominent among them Sen. Bob Menendez (D-NJ), who reiterated his strong support despite being embroiled in bribery and corruption charges. On the other hand, Rep. Nancy Pelosi (D-featist) and Sen. Barbara Boxer (D-CA) both declared opposition to Corker’s proposed legislation. It “represents an unnecessary hurdle to achieving a strong, final agreement,” Pelosi said, and Boxer added it “could derail a once-in-a-lifetime opportunity to deal with this looming threat.” Pelosi and Boxer clearly want to protect Barack Obama’s goal of getting a deal across the finish line before anyone can see what it entails. Sound familiar?

Both parties are digging in for a fight that will play out over the next two weeks.

Fortunately, as he so often does, the president provided some needed clarity on the issue late last week, which should make obvious where this deal is (or more accurately, isn’t) going. Except that would be President Hassan Rouhani of Iran, who could not have been clearer: “We will not sign any deal unless on the very first day of its implementation all economic sanctions against Iran are lifted all at once.”

Lest anyone think Rouhani was acting on his own, Supreme Leader Ali Khamenei added, “What has happened so far will neither guarantee the agreement itself nor its content. It will not even guarantee completion of the negotiations.”

Iran clearly does not agree that a deal has been reached even in principle, despite Obama’s triumphant announcement last week. Iran’s demand for complete sanctions relief on Day 1 is a non-starter, even for Boxer and most other Democrats.

We said last week we were guardedly optimistic this deal would collapse under its own weight, including among other things Iran’s demand for immediate sanctions relief. After hearing from Rouhani and Khamenei, we are even more optimistic. Since Iran has all but refused a deal that was about as favorable as they could have hoped for, we will soon be back where we started 18 months ago. Iran has refused to take “yes” for an answer. Now the P5+1 — and the larger UN — will have to decide if their word means anything, and whether Iran will be held to the terms of six UN Security Council Resolutions and the Non-Proliferation Treaty itself.