Issue Overview: History of the Mexico border By History.com, adapted by Newsela staff on 04.27.18 Word Count 911 Level 1060L

Image 1. A U.S. border patrol vehicle rides along the fence at the U.S.-Mexican border near Naco, Mexico, January 13, 2008. Photo by: Guillermo Arias for AP

The border between the United States and Mexico stretches for nearly 2,000 miles. It runs from the Gulf of Mexico to the Pacific Ocean, and touches the states of California, Arizona, New Mexico and Texas. The Rio Grande flows along 1,254 miles of the border, creating a natural boundary. West of El Paso, Texas, however, the border mostly lacks any natural geographic barriers.

This article is available at 5 reading levels at https://newsela.com. 1 Approximately 700 miles of barbed wire and fencing has been erected along the U.S.- Mexico border. The U.S. Border Patrol also utilizes thousands of cameras and underground sensors as well as aircraft, drones and boats to monitor the boundary.

Mexico became a country after winning its independence from Spain in 1821. Originally, it stretched as far north as the Oregon Territory. When Texas seceded from Mexico in 1836, it marked the beginning of the loss of a large part of Mexico's territory. That lost territory would later become the U.S. Southwest.

U.S. President James K. Polk was elected in 1844 on a pledge to enlarge U.S. territory. Relations with Mexico deteriorated after the United States annexed Texas in 1845. When Mexico refused an American offer to purchase California and New Mexico for $30 million, Polk dispatched 4,000 troops into land claimed by both countries. The disputed territory lay north of the Rio Grande and south of the Nueces River.

On April 25, 1846, Mexican forces attacked American troops stationed in the disputed area. Polk's opponents would later argue the president had provoked the Mexicans into the fight. In response, the United States declared war on Mexico. After a series of bloody battles, American forces captured the Mexican capital in September 1847.

Under the 1848 Treaty of Guadalupe Hidalgo, Mexico formally recognized the American annexation of Texas. It also agreed to sell more than one-third of its territory. For $15 million, the United States purchased more than a half million square miles of formerly Mexican land. The newly acquired territory included what later became the states of California, Arizona, New Mexico, Nevada and Utah, as well as parts of Colorado, Wyoming, Oklahoma and Kansas.

This article is available at 5 reading levels at https://newsela.com. 2 The modern border took shape following the Mexican-American War. A team of surveyors, soldiers and officials from both countries staked out the border from El Paso to Tijuana. The border originally moved west from El Paso on a straight line to the Gila River and then on another straight line to the Pacific Ocean south of San Diego. Following the Gadsden Purchase of 1853, the borders of Arizona and New Mexico moved farther south.

In the decades following the Mexican-American War, there were no federal limits on immigration from Mexico. Citizens from both countries passed freely across the border. It was Chinese immigrants, not Mexicans, that the United States first sought to keep from illegally crossing its southern border. Chinese immigrants had been banned since the passage of the Chinese Exclusion Act of 1882. Some tried to slip across the border disguised as Mexicans.

There was little restriction on the movement of Mexican citizens across the border until 1910, when a revolution broke out in Mexico. War at home led large numbers of Mexicans to seek safety in the United States. The fighting continued until 1920.

In 1916 the Mexican revolutionary Pancho Villa staged a deadly raid on Columbus, New Mexico. Following this attack, the United States tightened border security. Soldiers began patrolling the boundary, along with the Texas Rangers and government-sanctioned "home guards."

The first fence along the frontier was not erected until 1909. It was put up to stop the trans-border movement of cattle. Border towns erected fences during the 1910s, though most were built just to mark the boundary line and to channel people to official crossing points.

The United States began setting up border fences to restrict the movement of unlawful immigrants in 1993 when President Bill Clinton ordered the construction of a 14-mile barrier between San Diego and Tijuana. The Secure Fence Act of 2006 authorized the construction of 700 miles of border fencing. Work was completed in 2011.

This article is available at 5 reading levels at https://newsela.com. 3 In 2016, approximately 11.6 million Mexican immigrants lived in the United States. About half of them were in the country illegally.

President Donald Trump has vowed to prevent further illegal immigration. The centerpiece of his plan is the construction of an "impenetrable, physical, tall, powerful, beautiful, southern border wall." However, the project faces funding, environmental and legal obstacles.

Trump has claimed that 1,000 miles of new wall as high as 55 feet tall can be built for $18 billion. However, a study by independent experts estimates the cost to be $40 billion. The Mexican government has stated that it will not pay for the wall's construction, contrary to what Trump has promised. The U.S. Congress has also not been enthusiastic about Trump's wall. In March 2018, it set aside only $1.6 billion for the project.

In April 2018, President Trump announced that he was ordering National Guard troops to patrol the border. He said they would remain there until further progress is made on construction of the wall. The future of Trump's wall project remains unclear.

This article is available at 5 reading levels at https://newsela.com. 4