D. chairman of the joint chiefs of staff-d. the national security council was established in 1947 to ensure that both military and diplomatic viewpoints were heard in making foreign policy. the statutory membership is limited. others can be invited by the president to participate. for example, the secretary of the treasury is often involved although not a statutory member. during the ford administration, legislation was enacted to add the treasury secretary, but president ford vetoed it, stating that he did not want to make the group too large. the chairman of the joint chiefs of staff and the assistant to the president for national security affairs are both advisory and not statutory members.