WASHINGTON: US Secretary of State John Kerry has warned American lawmakers that Iran has already ‘mastered’ the technology to make fissile material and only a deal could stop it from making weapons.

Mr Kerry and other members of the Obama cabinet appeared before the House Foreign Affairs Committee on Tuesday afternoon to defend a nuclear deal with Iran signed earlier this month.

The House, where the rival Republicans have a controlling majority, was hostile to Mr Kerry and his colleagues who had several bouts of tense exchanges with the lawmakers.

Know more: Iran deal only viable option, Kerry tells senators

Republicans oppose the deal and have vowed to undo it. But to do so, they need to vacate a presidential veto for which they need support from at least 14 Democrats in the Senate, where the Republicans only have a simple majority.

“They have mastered the ability to produce significant stockpiles of fissile material. And you have to have that to make a nuclear weapon,” Mr Kerry told the panel. “We can’t bomb away that knowledge anymore than you can sanction it away.”

As he did during his appearance before the Senate Foreign Relations Committee on Thursday, Secretary Kerry warned that undoing the agreement, which was also signed by five other world powers – Britain, China, France, Germany and Russia – would isolate the United States.

“If we walk away, we walk away alone. Our partners are not going to be with us,” he said. “Instead they will walk away from the tough multilateral sanctions that brought Iran to the negotiating table in the first place.”

But his warnings had little impact on Republican lawmakers.

House Speaker John Boehner has vowed that his congressional caucus will “do everything possible to stop” the agreement.

Ed Royce, the committee’s chairman called the deal “a financial windfall” for Iran and “a cash bonanza, a boost to its international standing, and a lighted path towards nuclear weapons.”

He said the deal would take away a weapon the US had used effectively against Iran, the sanctions.

“Virtually all economic, financial, and energy sanctions disappear.” He said that the Obama administration was working on a presumption that Iran would abandon its nuclear weapons programme in return.

Secretary Kerry disagreed.

“Mr Chairman with all due respect, please, we are presuming no such thing — there is one objective here: to prevent (Iran) from getting a nuclear weapon,” he said.

“The American people see Iran as like a crocodile or a shark that does what it does and we’re saying we’re going to give the crocodile or shark a few more teeth,” said Congressman Scott Perry, Pennsylvania Republican.

Exasperated Kerry insisted that the administration was not doing no such thing. At one point, he practically yelled: “What this agreement is supposed to do is stop [Iran] from having a nuclear weapon. Now I want to hear somebody tell me how they are going to do that without this agreement.”

The notion of a better deal, he said, was a “unicorn fantasy”.

And a Democrat with strong ties to Israel, Sander Levin, agreed with Mr Kerry. He announced he would support the agreement, a decision Mr Kerry pointed out during the hearing.

“I believe that Israel, the region, and the world are far more secure if Iran does not move toward possession of a nuclear weapon,” Mr Levin. “I believe the agreement is the best way to achieve that.”

Published in Dawn, July 30th, 2015

On a mobile phone? Get the Dawn Mobile App: Apple Store | Google Play