Why is the country called the United Mexican States and not Mexico?
Throughout its history, the territory we know today as Mexico has had different names. Currently, its official name, as it appears in the Constitution, is the United Mexican States. The country has been called this way since 1917. You can read about why here.
The names that the territory that we currently call colloquially Mexico has had are
1. Kingdom of New Spain (1535) during the Colony.
2. Mexican America (Sentiments of the Nation, proposed in the Congress of Chilpancingo in 1813, which was headed by José María Morelos).
3. Mexican Empire (1821-1823).
4. Mexican Nation (Constitution of 1824).
5. Mexican Republic (Constitution of 1857).
6. Mexican Empire (1863-1867).
7. United Mexican States (in the Constitution of 1824 this name had already been used but it was not taken up again until 1917; in the Constitution of 1857, in addition to the Mexican Republic, the country was called that).
In December 1916, prior to the promulgation of the 1917 Political Constitution, a controversy arose over the name the country would be given. There were those who supported maintaining the name of the United Mexican States and those who proposed it be called the Mexican Federal Republic.
The Reform Commission, which proposed the name of the Mexican Federal Republic, argued that the first name imitated the name of the neighboring country: the United States of America, so they considered it necessary to change it. The Commission also argued that people identified more with the name of Mexico. In response to the opponents of this proposal, the Commission also pointed out that if the use of the word Republic bothered them, because it was associated with centralism or with the idea of a unitary Republic, that was why the word Federal would also be used.
On the other hand, the defenders of the denomination United Mexican States maintained that such name was necessary in respect to the federalism prior to the promulgation of the Constitution of 1824, due to which the states had united in a federation for their representation abroad but maintaining their sovereignty.
Finally, the 1917 Constitution was promulgated with the name of the United Mexican States, so since that year, the country has been officially called that way.
Proposal to change the name
Last Monday, Morena's congressman Juan Martinez Flores presented an initiative to change the official name of the country to "Mexico", instead of "United Mexican States", and therefore, the name of the Political Constitution.
Among other reasons, he stated that "in essence, since our country is a republic under a federal, representative and sovereign pact, Mexico is precisely the name that gives sense and essence to our nation; the name of Mexico contains the idea of autonomous and independent states within it and that represent a federal pact towards the outside".