Quoting russell@coker.com.au (russell@coker.com.au):
Also if we can just ignore treaties why does the TPP have to be enforced? Can we ignore that one too? Why does the US refuse to sign so many treaties if they can just be ignored?
Off the top of my head, often primarily for reasons of domestic politics and legal consequences if they were to be adopted. Separately from that: The term 'treaty' is a problematic one within the _internal_, domestic USA legal framework because the meaning is, in software engineering terms, overloaded. Or to put it another way, the US Constitution dictates particular requirements and powers for a particular class of thing that it calls 'treaties', but most things called 'treaties' inside the USA are not in that class, but rather one of two other classes. Meanwhile, the meaning of the term in international law is clear and consistent -- and all three things with domestic differences are all just called 'treaties' from an outside-USA perspective. Covered at: https://en.wikipedia.org/wiki/Treaty_Clause Article II of the Constitution (its major division defining the Executive Branch), Section 2, Clause 2 empowers the President to propose and be chief negotiator with foreign powers for written agreements that if then confirmed by vote of at least 2/3 of the US Senate, they become part of the body of U.S. domestic law, co-equal with statutes passed by Congress. Those are called 'Article II treaties', the only things _strictly_ qualifying as treaties. However, more often, the domestic side of an agreement with foreign powers gets implemented via a 'congressional-executive agreement (CEA)', an instrument negotiated by the President and then ratified by a regular majority of each house of Congress, or a 'sole-executive agreement', an agreement negotiated by the President alone without Congressional approval. Congressional-executive and sole-executive agreements are valid if they concern temporary matters. If they would purport to bind future Congresses or future Presidents, this can be done only with an Article II treaty. The third type, sole-executive agreement, is the most limited in its power: To be valid, it must need for enforcement only the defined powers of the Executive Branch such as custody of foreign policy, the role of commander-in-chief of the armed forces, and so on. If the agrement's scope requires use of powers reserved to the Legislative Branch (Congress), then one of the other forms of agreement would be required. As domestic law co-equal with Congressional legislation, all three types of agreement can be amended by subsequent acts of Congress. Also, just like domestic law, they may be subject to review and possible vacating by U.S. courts on constitutional grounds. Anyway, it has always and everywhere been the case that a sovereign power can ignore (abrogate) a treaty.