An agreement to curb Iran’s nuclear program could create a bonanza for U.S. defense contractors who already are benefiting as the Obama administration tries to assuage Israeli and Gulf Arab concerns by cutting deals for more than $6 billion in military hardware.

The details of a potential deal being negotiated between Iran and six world powers — China, France, Germany, Russia, the U.K. and U.S. — would determine what steps the U.S. takes to help its allies. A nuclear agreement is likely to prompt Mideast partners to seek improved defense systems from American contractors such as Boeing Co., Lockheed Martin Corp. and Raytheon Co. as well as weapons-makers in France and elsewhere.

“In theory, an Iran deal could lead to a reduction in tensions in the region that would reduce the demand for advanced weaponry,” said William Hartung, director of the Arms and Security Project at the Center for International Policy in Washington. “In the short-term, a deal could actually boost the demand for arms.” […]