00:00 President Trump's declaration of a national emergency at the U.S.-Mexico border and his push for a border wall are explored in this episode of Throughline from NPR.

01:54 President Trump's aggressive rhetoric and use of force at the U.S.-Mexico border is not new, as past American presidents have also responded with force to events happening at the border.

04:08 In the 20th century, the United States relied on Mexican labor during World War II through the Bracero Program, but after the war ended, illegal immigration from Mexico increased due to a lack of sufficient guest worker visas, leading President Eisenhower to launch Operation Wetback in 1954.

06:08 Operation Wetback changed the landscape of border security, ramping up immigration enforcement and leading to the arrest and deportation of people in the US illegally anywhere in the country, not just at the border.

08:01 The murder of a US drug enforcement agent by a drug cartel in 1985 marked a turning point in perceiving drug traffickers as national security threats and led to the United States considering the war on drugs as an actual war, resulting in a bipartisan pattern of US presidents responding with greater force in their immigration strategies, including deploying the Border Patrol in a military formation and hiring more border guards.

10:10 In response to the perceived threat of terrorism, the Department of Homeland Security was created, leading to the deployment of National Guard members and the construction of a 700-mile fence along the border, as well as increased deportations of illegal immigrants.

12:04 Aggressive action at the border has become an American political tradition, and while President Trump's border policies are a defining feature of his presidency, they are not new or unique to him.