Dependence on contractual power has declined since World War II, as presidents increasingly turn to the use of executive agreements as a means of ensuring unilateral control of U.S. foreign relations. If the president acts unilaterally, the agreement is called a “single executive agreement.” If the president acts with the agreement of a simple majority of both houses of Congress, the agreement is called “legislative and executive agreement.” Presidents have a “margin of appreciation” in deciding whether they wish to pursue an international agreement in the form of a treaty, a single executive agreement or in the form of a legislative and executive agreement. The Speaker`s decision generally depends on political factors, including the likelihood of obtaining Senate approval. Presidents have often chosen to exclude the Senate from concluding some controversial and historic international pacts on the channel of executive agreements, including the basic destructive agreement with Britain in 1940, the Yalta and Potsdam accords of 1945, the Vietnam Peace Agreement of 1973 and the Sinai Accords of 1975. Congressional efforts to curb the practice of executive agreements and stem the tide of unilateralism have been largely unsuccessful. The first and most important effort came in 1951, when Senator John Bricker proposed a constitutional amendment to limit the use and impact of executive agreements and treaties within the United States. Bricker Amendment supporters, including the leaders of the American Bar Association, found virtue in the proposal for a variety of reasons. Some, as Alexander DeConde explained, “have become angry at executive agreements like Yalta`s” and have tried to reduce the president`s unilateralism on foreign policy.
Others feared the impact of treaties such as the United Nations Charter, the Genocide Convention and the United Nations draft peace on human rights within the United States. Still others supported them as a useful “isolationist” response to “the internationalism of Franklin Roosevelt and Harry Truman. The executive`s purported intention to make full use of executive agreements in the implementation of post-war colonies was repeatedly cited during the Senate debate during the 1943 session of Congress.