The Powers of the Union is a constitutional

Constitution of Mexico

The Political Constitution of the United Mexican States is the current constitution of Mexico. It was drafted in Santiago de Querétaro, in the State of Querétaro, by a constitutional convention, during the Mexican Revolution. It was approved by the Constitutional Congress on February 5, 1917...

 term to refer to the three branches of the Mexican

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 government jointly:

• the executive power
  Executive Power
  Executive Power is Vince Flynn's fifth novel, and the fourth to feature Mitch Rapp, an American agent that works for the CIA as an operative for a covert counter terrorism unit called the "Orion Team."-Plot summary:...
  
  , the president of the United Mexican States
  President of Mexico
  The President of the United Mexican States is the head of state and government of Mexico. Under the Constitution, the president is also the Supreme Commander of the Mexican armed forces...
  
  ;
• the legislative power, the Congress of the Union, and
• the judicial power, the Supreme Court of Justice of the Nation
  Supreme Court of Justice of the Nation
  The Supreme Court of Justice of the Nation is the highest federal court in the United Mexican States. It consists of a President of the Supreme Court and ten Ministers who are confirmed by the Senate from a list proposed by the President of the Republic.Justices of the SCJN serve for fifteen...
  
  .

These are the three branches of government, or powers, of the federated "Union" of the thirty-one constituent states. The Powers of the Union are also referred to as the Supreme Power of the Federation (Supremo Poder de la Federación). Mexico City

Mexico City

Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...

 is constitutionally defined as the federal district

Federal district

Federal districts are a type of administrative division of a federation, under the direct control of a federal government. They exist in various countries and states all over the world.-United States:...

and seat of the "Powers of the Union".