U.S. congressmen said on Friday that a primary reason the U.S. needs to deploy the Terminal High-Altitude Area Defense (THAAD) system to South Korea is China’s failure to rein in the North.

“If China were doing enough to curb North Korea’s misbehavior, then there would be no need for THAAD at all,” Representative Jim Cooper (D-Tennessee) told the Yonhap News Agency.

Cooper, a 12-term congressman representing the Nashville area and a member of the House Committee on Armed Services, was in South Korea as part of a bipartisan congressional delegation headed by Representative Mike Rogers, a Republican from Alabama. Rogers