After a decade of fighting Mexico had finally stumbled onto independence and ratified the Constitution of 1824, which was built on the same democratic principles of the Cortes of Cadiz and the Constitution of 1812. However, Texas wouldn't stay part of Mexico for very long. In fact, by the time Spain recognized the independence of Mexico, Texas had already started their own revolution. Only lasting a year, the Texas Revolution saw the secession of the Tejas territory into an independent republic that would eventually join the expanding United States.

The Republic of Texas was a sovereign state in North America that lasted from 1836 to 1846, although Mexico considered it a rebellious province during its entire existence. The citizens of the republic were known as Texians. The region of the Mexican state of Coahuila y Tejas, commonly referred to as Mexican Texas in class, declared its independence from Mexico during the Texas Revolution in 1835–1836, when the Centralist Republic of Mexico abolished federalism from states of the Mexican federal republic by repealing the Constitution of 1824. The major fighting in the Texas war of independence ended in 1836, but the Mexican Congress refused to recognize the independence of the Republic of Texas, since the agreement was signed by Mexican President General Antonio López de Santa Anna while he was a prisoner. Conflicts between Mexico and Texas continued into the 1840s. The United States recognized the Republic of Texas in March 1837 but declined to annex the territory.

The Republic-claimed borders (which were disputed by Mexico) were based upon the Treaties of Velasco. The eastern boundary had been defined by the Adams–Onís Treaty of 1819 between the United States and Spain, which recognized the Sabine River as the eastern boundary of Spanish Texas and western boundary of the Missouri Territory. Under the 1819 Adams–Onís Treaty, before Mexico's 1821 independence. The republic's southern and western boundary with Mexico was disputed throughout the republic's existence, since Mexico disputed the independence of Texas. Texas claimed the Rio Grande as its southern boundary, while Mexico insisted that the Nueces River was the boundary. In practice, much of the disputed territory was occupied by the Comanche and outside the control of either state, but Texian claims included the eastern portions of New Mexico, which was administered by Mexico throughout this period.

Texas seceded from Mexico in 1836, spurred on primarily by American settlers in the former Mexican territory against the government of Santa Anna. After the final engagement at San Jacinto in 1836, there were two different visions of the future of Texas: one as a state of the United States and the other as an independent republic. The first President of the Republic of Texas, Sam Houston felt that the newly independent country, lacking hard currency and still facing threats from Mexico, could not survive on its own. The other was promoted by second Texas president Mirabeau B. Lamar, who felt that it was Texas's destiny to be a nation that extended from the Louisiana border to the Pacific Ocean. For this reason, Lamar is considered the father of Texas nationalism.

Sam Houston was elected as the first President of the Republic of Texas in 1836. Stephen F. Austin, known as the Father of Texas, died the same year after serving as Secretary of State for two months. Five sites served as temporary capitals of Texas (Washington-on-the-Brazos, Harrisburg, Galveston, Velasco and Columbia), before President Sam Houston moved the capital to Houston in 1837. The next president, Mirabeau B. Lamar, moved the capital to the new town of Austin in 1839.

Internal politics of the Republic centered on two factions. The nationalist faction, led by Lamar, advocated the continued independence of Texas, the expulsion of the Native Americans (Indians), and the expansion of Texas to the Pacific Ocean. The Republic under Lamar incurred large-scale debt, and suffered from a poor economy and inadequate defenses, which led to the annexation of Texas into the United States in 1845. Since then, the state's time as an independent nation has been the basis of a lasting sense of national identity.

Their opponents, led by Houston, advocated the annexation of Texas to the United States and peaceful coexistence with the Indians, when possible. The Texas Congress even passed a resolution over Houston's veto claiming California for Texas. The newer western regions of the Republic preferred a more centralized government, while the cotton country, particularly east of the Trinity River advocated for federalism to protect their “right” to own slaves. Oh boy, what could go wrong ? *cough cough* Civil War *cough cough*

Texas: A Constitutional Republic

In Texas, history is reflected not only in the content of the constitution, but in the number of constitutions under which the state has been governed. Texas was first governed by Spain, and then Mexico before becoming the independent Republic of Texas.  Each new Texas constitution featured new amendments, or changes to the Constitution. By the time Texas joined the United States they had implemented a Bill of Rights similar to those of the United States.

Constitution of Coahuila y Tejas, 1827

Texas was governed as a part of Mexico under the Mexican Constitution of 1824. Established as a federal republic, each state could write its own constitution. Combined as a single state, Texas and Coahuila established a constitution in 1827 with separation of powers into three branches of government: the executive, legislative and judicial. Under this constitution, legislative power was delegated to a legislature. Executive power was vested in a governor and vice-governor, elected to four-year terms by popular vote. The governor could recommend legislation, grant pardons, lead the state militia, and see that the laws were obeyed. Judicial authority was vested in state courts that oversaw minor criminal trials and civil cases, otherwise known as due process. The courts could not interpret the law, and misdemeanor cases were tried by a judge without a jury. Texans ignored two provisions, one that required Catholicism as the state religion and the other that did not recognize slavery.

The Republic of Texas Constitution, 1836

Because of escalating tensions between Texas and Mexico, Texas assembled an ad-interim government and declared its independence in 1836, established the Republic of Texas, and adopted a new constitution. The Texas Constitution of 1836 copied major portions from the U.S. Constitution. Its features included separation of powers into three branches—legislative, executive, and judicial—with a system of checks and balances. It created a bicameral legislature, with a House of Representatives and a Senate. Representatives and Senators served terms of one and three years, respectively. The executive resembled the American president who was elected by popular vote. The judiciary was four-tiered, with justice, county, district, and supreme courts. The constitution also recognized slavery, provided for male suffrage, contained a Bill of Rights, and excluded citizenship to African Americans and Native Americans. Although the document did contain an amendment process, it was so complex that none were ever adopted.

The State Constitution of 1845

When Texas joined the United States, a new constitution was necessary. The U.S. Congress accepted the state’s charter in 1845 (annexation), and Texas became the twenty-eighth state to join the Union. The Texas Constitution of 1845 was a document of broad, general principles that allowed state government the flexibility to solve policy problems as they arose under federalism. It continued the tradition of a bicameral legislature, and a governor. The attorney general and secretary of state were appointed by the governor and confirmed by the Senate. The governor could convene the legislature, was the commander-in-chief of the state militia, granted pardons and reprieves, and could veto legislation, which could be overridden by a two-thirds vote of both houses. The judiciary consisted of a Supreme Court, district courts, and additional courts created by the legislature. Judges to the supreme and district courts were appointed by the governor. Amendments required proposal by a two-thirds (supermajority) vote of both houses of the legislature and ratification by a majority popular vote. Only one amendment was approved by Texans.

The Constitution of 1845 was also heavily influenced by Jacksonian Democracy, a political philosophy named for the democratization policies implemented by President Andrew Jackson during the 1830s to 1850s. Jackson attacked a ruling class which, he argued, dominated an activist government, concentrating financial and political power to the benefit of a relatively small number of elites. Jackson sought to increase popular participation in government and one of his key policies for breaking the elitist hold on government was to extend voting rights (suffrage) and expand the number of political officials subject to popular election. The long ballots with which Texas voters still contend are a direct legacy of Jacksonian Democracy and the Constitution of 1845.