Professor Alan Dershowitz
Professor Alan Dershowitz Gideon Markowicz/Flash90

US attorney Alan Dershowitz has given up hope that Congress could block the Iran nuclear deal – but he has a plan to make sure the US is ready if Iran “cheats” and tries to acquire nuclear weapons.

He says Congress should authorize military force now, in an interview with World Net Daily / Radio America.

“The deal itself starts with a re-affirmation by Iran that it will never, ever, under any circumstances seek to obtain, develop or secure nuclear weapons,” he explained. “Nobody has ever heard of that because there is, I believe, a private, secret agreement between the United States and Iran that that part of the deal is not enforceable."

And yet, he explained, this statement by Iran could be the key to making a bad deal better.

The US needs to now say, “'We accept as American policy Iran's re-affirmation, Iran's own promise that it will never, ever, under any circumstances, seek to develop nuclear weapons,'” he elaborated.

"We have to make that an enforceable, integral part of the deal, regardless of what the president of the United States had as a side deal with the Iranians. The deal itself says that. We're entitled to hold them to their word," Dershowitz said.

If Iran violates that commitment, he added, force should be authorized in advance.

"We need deterrence," he said. "We need to make sure that the Iranians know that there is a military option on the table if they cheat and rush to develop a bomb. Right now, they do not believe that the president of the United States will ever engage in military action against them. They think they're free to do whatever they want."

We need Congress to authorize the president in advance to use whatever is necessary, including military, to prevent Iran from ever developing nuclear weapons. I think if we get Congress to pass such a statute, it will send a very powerful message."

Dershowitz admits Obama may refuse to sign that type of legislation, but it would put the president in a curious position.

"If he vetoes it, he's going to have a hard time explaining to his Democratic colleagues why he's vetoing a law that only repeats what's in the deal, number one, and number two, which repeats what he has already said. He believes he has the authority and the will to use whatever is necessary to prevent Iran from developing weapons," he said.