"Legislation to reauthorize Trade Promotion Authority (TPA)--sometimes called 'fast track'--the Bipartisan Congressional Trade Priorities and Accountability Act of 2015 (TPA-2015), was signed into law by President Obama on June 29, 2015 (P.L. 114-26). If the President negotiates an international trade agreement that would reduce tariff or nontariff barriers to trade in ways that require changes in U.S. law, the United States can implement the agreement only through the enactment of legislation. If the trade agreement and the process of negotiating it meet certain requirements, TPA allows Congress to consider the required implementing bill under expedited procedures, pursuant to which the bill may come to the floor without action by the leadership, and can receive a guaranteed up-or-down vote with no amendments."
CRS Report for Congress, R43491
Congressional Research Service: https://crsreports.congress.gov/