United States law
In US law, the term "treaty" is used in a more restricted sense than in international law. US law distinguishes what it calls treaties from congressional-executive agreements and sole executive agreements. All three classes are equally treaties under international law; they are distinct only from the perspective of internal US law. The distinctions are primarily concerning their method of ratification (by the 2/3rds of the Senate, by normal legislative process, or by the President alone) and their relationship to US domestic law. Article II, Section 2 of the United States Constitution grants power to the President to make treaties with the "advice and consent" of two thirds of the Senate. This is different from normal legislation which requires approval by simple majorities in both the Senate and the House of Representatives. However, throughout U.S. history, the President has also made "international agreements" through congressional-executive agreements (CEAs) that are ratified with only a majority from both houses of Congress, or sole executive agreements made by the President alone. Though the constitution does not expressly provide for any alternative procedure and although some noted constitutional scholars, such as Laurence Tribe, believe that CEAs are unconstitutional, the Supreme Court has considered these agreements to be valid, and that any disagreements are a political question for the executive and legislative branches to work out amongst themselves. In addition, U.S. law distinguishes between self-executing treaties, which do not require additional legislative action, and non-self-executing treaties which do require the enactment of new laws. These distinctions of procedure and terminology do not affect the binding status of such agreements under international law. Nevertheless, they do have major implications under U.S. domestic law. In Missouri v. Holland, the Supreme Court ruled that the power to make treaties under the U.S. Constitution is a power separate from the enumerated powers of the federal government, and hence the federal government can use treaties to legislate in areas which would otherwise fall within the exclusive competence of the states. By contrast, a congressional-executive agreement can only cover matters which the Constitution explicitly places within the powers of Congress and the President, while an executive agreement can only cover matters within the President's authority or matters in which Congress has delegated authority to the President. While the ratification process for treaties is different from the process for CEA's, which venue is more advantageous for passage depends on the relevant circumstances. In general, arms control agreements are ratified by the treaty mechanism because it is simpler to go through one house of congress than two. At the same time, trade agreements are generally voted on as a CEA because the two-thirds requirement makes it possible for agricultural interests to veto any tariff reduction in the Senate. The United States takes a different view concerning the relationship between international and domestic law than many other nations, particularly in Europe. Unlike nations which view international agreements as always superseding national law, the American view is that international agreements become part of the body of U.S. federal law. As a result, Congress can modify or repeal treaties by subsequent legislative action, even if this amounts to a violation of the treaty under international law. The most recent changes will be enforced by U.S. courts entirely independently of whether the international community still considers the old treaty obligations binding upon the U.S. Additionally, an international agreement that is inconsistent with the U.S. Constitution is void under domestic U.S. law, the same as any other federal law in conflict with the Constitution, and the Supreme Court could rule a treaty provision to be unconstitutional and void under domestic law, although it has never done so. The constitutional constraints are stronger in the case of CEA and executive agreements, which cannot override the laws of state governments. The Supreme Court has also ruled in Goldwater v. Carter, 444 U.S. 996 (1979) that the President has the power to unilaterally abrogate a treaty without the consent of Congress or the Senate. The case in question involved President Jimmy Carter's termination of a defense treaty with the Republic of China on Taiwan. The U.S. is not a party to the Vienna Convention. However, the State Department has nonetheless taken the position that it is still binding, in that the Convention represents established customary law. The U.S. habitually includes in treaty negotiations the reservation that it will assume no obligations that are in violation of the U.S. Constitution. However, the Vienna Convention provides that states are not excused from their treaty obligations on the grounds that they violate the state's constitution, unless the violation is manifestly obvious at the time of contracting the treaty. So for instance, if the US Supreme Court found that a treaty violated the US constitution, it would no longer be binding on the US under US law; but it would still be binding on the US under international law, unless its unconstitutionality was manifestly obvious to the other states at the time the treaty was contracted. It has also been argued by the foreign governments (especially European) and by international human rights advocates that many of these US reservations are both so vague and broad as to be invalid (what is in violation of the US constitution? anything that the US judiciary claims is), and also are invalid as being in violation of the Vienna Convention provisions referenced earlier.
http://connaught.road.en.wikimiki.org/e ... +Agreement