Prior to joining White & Case, Ismael Reyes-Retana Tello worked in the public sector, with 25 years of experience collaborating in several agencies and entities of the Federal Public Administration.  His performance as Director General of Legal Studies of the Presidency, Deputy Legal Counsel to the President, and until February, 2008 as Federal Deputy Attorney General for Tax Matters and Deputy Counsel to the Ministry of Finance and Public Credit (Subprocurador Fiscal Federal), has consolidated him as a leading specialist in constitutional and administrative law in Mexico.

For a period of 9 years, Mr. Reyes-Retana served as  the Presidential delegate before the Supreme Court of Justice of the Nation, managing constitutional controversies, during which time he participated in more than 250 constitutional cases with respect to a broad range of matters such as electric energy, anti-trust issues, territorial limits conflicts, Integral Port Administration, tax exemptions, tax coordination, banking security and protection; the Federal Expense Budget; the audit by the House of Representatives to Fobaproa (FDIC equivalent); education decentralization, ecologic reserves, alternate airport of Mexico City; impeachment; international treaties; the labor framework applicable to decentralized organisms, Presidential appointment authority; constitutional reform with respect to indigenous groups, public security and social security.

Among his more recent collaborations is his participation in the constitutional controversies in which the Supreme Court declared that the Auditoría Superior de la Federación (equivalent to the U.S. General Accounting Office) is not entitled to order certain actions to the Federal Executive Branch.  Likewise, he actively collaborated in the constitutional controversy by means of which the Supreme Court resolved that the President is entitled to veto the Federal Expense Budget.

Mr. Reyes-Retana has experience also in preparing legislative bills, as during his time with the Office of the Counsel to the President and the Office of the Federal Attorney General for Tax Matters, he participated in the formulation of several initiatives of constitutional and legal reform, as well as in the drafting of Presidential decrees.

Additionally, he has collaborated as legal advisor to the Federal Executive Branch in several transactions and in the implementation of governmental actions of great relevance.

Mr. Reyes-Retana has participated in several collegiate bodies within the Federal Government, notably including, among others, the Commission for Legal Studies of the Federal Government, the Interministerial Commission of Divestment, the Interministerial Commission of Expense and Financing and the Governing Board of the National Institute of Statistics.