By reaffirmation of legal opinion number 3/2013 (9a.), Mexico's Supreme Court of Justice of the Nation (SCJN) recently issued the legal opinion titled "Foreign Trade. The extraordinary authority to legislate granted to the President of the Republic in Constitutional Article 131, second paragraph, which not only includes the ability to increase, decrease or eliminate export or import duties issued by Congress and to create others, but also to repeal such." In this legal opinion, the SCJN definitively confirms the criteria for the dismissal of an amparo proceeding for a violation of the regulatory authority conferred upon the President of the Republic in Constitutional Article 131, second paragraph, to increase, decrease or eliminate the import and export tariff rates issued by Congress, which do not expressly allow for the "repeal" of such tariffs. Contrary to such, the SCJN has held that the clear intent of the legislature was to allow the tax system to be consistent with the principles of flexibility and efficiency, which are achieved only if the President has legal and material authority to adjust tariffs according to the economic needs of the country at any given moment in time. As a result, the SCJN concludes that among the meanings of the term "modify" are to alter, vary and to repeal, which in practice has no binding effect on the legislature, as it can supersede the President's determination by enacting another law or decree. This legal opinion is important given the controversy surrounding the authority of the President, which has been under review since 2001. This legal opinion is published in the Weekly Federal Court Reporter and its Gazette, Book XVII, February 2013, Volume 1, page 298.