Fred Bergsten’s concise explanation of why the US invented TPA, formerly “fast track”:

Our unique constitutional system – under which Congress is responsible for “foreign commerce” but the president has authority to negotiate with other governments – has required the creation of special procedures to mesh with the parliamentary systems of other countries where executive and legislative branches almost always work together. Without arrangements that assure reasonably prompt congressional action on agreements negotiated by the president, other countries legitimately fear that Congress will simply let deals languish, or insist on further concessions…

Current and former chief trade officials of three of the world’s largest trading entities have told me that, since the House action, the U.S. has lost all credibility. In other words, the “time out” proposed for trade policy by one of the major presidential candidates – a central goal of the opponents of globalization – has already been called.