By Karoun Demirjian, defense and foreign policy correspondent for Washington Post

Even if the Obama administration manages to keep the Iran nuclear agreement alive, the next Iran battle in Congress is closer than you think.
Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) recently issued a threatening prediction, surmising that no matter how Congress ends up voting in September, lawmakers will try to pass an extension of existing Iran sanctions this fall – even if Iran might consider that a breach of the nuclear pact.
“My guess is that one of the first things Congress will do when we finish this debate – I would, say, give it 60 days – we will pass that extension,” Corker said, referring to the Iran Sanctions Act (ISA), which is due to expire in 2016. “Even though Iran says that they believe anything to that effect would be in violation” of the nuclear pact.
ISA seeks to curb Iran’s nuclear and missile activities, as well as its support for terrorism by targeting sanctions at the country’s trade, energy, banking, and defense sectors. It was first adopted in 1996 as part of a joint package imposing sanctions against Libya, but was amended several times since and is now exclusively focused on Iran.
But extending ISA is no simple matter, as some of the sanctions within it are aimed at punishing Iran’s nuclear aspirations — posing a problem for the entire nuclear deal.
But ISA expires in 2016, and many lawmakers feel that failing to extend it would be cheating the U.S. out of its own security prematurely. The U.S. has up to eight years before the nuclear deal mandates rolling back nuclear sanctions under the Iran deal and hawkish lawmaker don’t want to give up that stick too soon.
“We have snapback provisions, right? Well, if you don’t extend ISA, you have nothing to snap back to,” Corker said Wednesday, recalling how Sen. Robert Menendez [D-N.J.] asked administration officials last month if they would support Congress extending ISA. “And the answer is, first of all, they’ve said on multiple occasions: now is not the time.”
Relying on ISA as a fail-safe could assuage the concerns of some lawmakers worried about having as punishing a backstop as possible should Iran not live up to its side of the deal.
The current proposal to extend ISA, from Menendez and Sen. Mark Kirk (R-Ill.), would take the law through 2026 – long after the maximum eight years after which Congress must lift its nuclear-related sanctions under the nuclear agreement. But even if the extension were shorter, administration officials still do not seem comfortable discussing the idea.
 “We can’t take the nuclear sanctions, put a different label on them and put them right back into place,” Lew told Sen. Kelly Ayotte (R-N.H.) at a hearing last month before the Senate Armed Services Committee, adding that the U.S. would simply have to make the case “the institutions should be sanctioned for their behavior on terrorism and human rights and regional destabilization…all of our sanctions that apply in that area still stand.”
Congress could ostensibly work out a way to pass a modified ISA extension that would resolve everyone’s concerns.
But Republican congressional leaders clearly don’t want to wait that long to make their next Iran move.
“I think there’s going to be a huge pent-up demand from both sides of the aisle to pass legislation 30 or 60 days after the fact,” Corker said. “They’ve got all kinds of language in multiple places to keep us from adding sanctions…my guess is they know they cannot sustain that on the extension of 2016.”
And if an extension of the ISA throws the plan into disarray? Well, that may just be another Iran issue where the country’s policy gets decided in a fight over how well Congress can muster a super-majority against the president’s veto pen.

The Washington Post, 11 August 2015