He said the move would also prompt Germany and Italy to buy European-built alternatives to upgrade their air and missile defense systems, and could undermine U.S. efforts to argue for more defense cooperation and burden-sharing.

U.S. withdrawal from MEADS would also jeopardize other ongoing cooperative acquisition programs and purchases of defense equipment from the U.S., he said. Italy has already scaled back its planned procurement of F-35 fighter jets, also built by Lockheed.

Kendall and Panetta both argued that failure to finish funding development of the MEADS program would also make it difficult for the United States and its partners to harvest certain radar, software and electronic technologies from the joint program.

That in turn, he said, would force the Pentagon to pay for new development efforts in the future.

Panetta said congressional failure to fund MEADS would also diminish a major breakthrough reached on missile defense at the NATO summit in Chicago in May, where NATO countries said they had reached “interim capability” on ballistic missile defense as an initial step towards establishing a NATO missile defense system.

“The United States relies on allies to share the burden of peacekeeping and defense in coalition activities,” Panetta said. “In this context, I believe that it is important to live up to our commitments to our allies.”

Earlier this month, German and Italian officials warned U.S. lawmakers that their plans to cut off funding for the MEADS program would endanger U.S. ties with their countries.