Editing 1840s (section)

==== Mexico ====
{{See also|Territorial evolution of Mexico|Centralist Republic of Mexico|Antonio López de Santa Anna}}
The 1840s for Mexico were the end of the [[Centralist Republic of Mexico|centralist government]] and the waning years the "Age of Santa Anna". In 1834, President [[Antonio López de Santa Anna]] dissolved Congress, forming a new government. That government instituted the new Centralist Republic of Mexico by approving a new centralist constitution ("[[Siete Leyes]]"), From its formation in 1835 until its dissolution in 1846, the Centralist Republic was governed by eleven [[President of Mexico|presidents]] (none of which finished their term). It called for the state militias to disarm, but many states resisted, including [[Mexican Texas]], which won its independence in the [[Texas Revolution]] of 1836.

The [[Republic of the Rio Grande]] declared its independence from Mexico in January 1840. However, the border with Texas was never determined (whether the [[Nueces River]] or the [[Rio Grande]]). The new Republic fought a brief and unsuccessful war for independence, returning to Mexico late in the year.

In 1841, Generals [[Antonio López de Santa Anna|Santa Anna]] and [[Mariano Paredes (President of Mexico)|Paredes]] led a rebellion against [[Anastasio Bustamante|President Bustamante]], resulting in Santa Anna becoming president of the [[Centralist Republic of Mexico|centralist government]] for a fifth time . Local officials in Yucatán declared independence in 1841, opposing strong autocratic rule and demanding the restoration of the [[1824 Constitution of Mexico|Constitution of 1824]], thus establishing the second [[Republic of Yucatán]].

In 1842, the region of [[Soconusco]] was annexed by Mexico as part of the state of [[Chiapas]], following the dissolution of the [[Federal Republic of Central America]].

In 1846, [[Mariano Paredes (President of Mexico)|President Paredes]] and the Congress of Mexico declared war at the beginning of the Mexican–American War. Paredes' presidential successor was deposed in a coup, replaced by [[José Mariano Salas]]. Salas issued a new decree that restored the [[1824 Constitution of Mexico|Constitution of 1824]], ending the Centralist Republic and beginning the [[Second Federal Republic of Mexico]]. After the conclusion of the Mexican–American War, [[José Joaquín de Herrera]] became the second president of Mexico to finish his term (Mexico's first president completed his in 1829). It was during this time that Yucatán reunited with Mexico. A decisive factor for the reunion was the [[Caste War of Yucatán]] (a revolt by the indigenous [[Maya peoples|Maya]] population) for which Yucatán initially sought help from Spain, the United Kingdom, and the United States, but ultimately reunited with Mexico for help.

Herrera peacefully turned over the presidency to the winner of the Federal Elections of 1850, General [[Mariano Arista]]. Despite being exiled from Mexico in 1848, Santa Anna would [[Antonio López de Santa Anna#President for the last time, 1853–1855|return to the presidency one last time]] during the [[1850s]].