Trump has frequently used the word invasion to describe undocumented immigrants coming over the southern border. In June 2018, he tweeted about border crossers, “We cannot allow all of these people to invade our Country. When somebody comes in, we must immediately, with no Judges or Court Cases, bring them back from where they came.” He amped up his “invasion” talk that November, shortly before the midterm elections, as part of his scare tactics concerning the Central American “caravan.” “Some people call it an ‘invasion,’” Trump said at the time. “It’s like an invasion. They have violently overrun the Mexican border.” And just this week, The New York Times reported that more than 2,000 Facebook ads from Trump’s reelection campaign have amplified his message by using the word invasion.

Read: How Trump obscures mass shootings with doublespeak

The El Paso suspect is believed to have posted his screed online minutes before carrying out the shooting that left 22 dead and at least 26 others injured. In it, he called his attack “a response to the Hispanic invasion of Texas.” And while the El Paso manifesto seeks to absolve Trump from blame for the shooting, its language about an ongoing “invasion” from the south is distinctly Trumpian. It also mirrors the longer list of grievances from the white supremacist charged in the shooting attacks at mosques in Christchurch, New Zealand, in March. The New Zealand shooter wrote of wanting to “deport those invaders already living on our soil.”

The American brand of nativism has long relied on menacing images of immigrant invaders. The “invasion” trope has gone hand in hand with similar metaphors of contamination and infestation. (Trump has drawn on the rhetorical figure of “infestation” as well, as I explored recently.) Democrats, the president has said on Twitter, “want illegal immigrants, no matter how bad they may be, to pour into and infest our Country.” Since the El Paso shooting, Trump’s critics have pointed to such rhetoric as a contributing factor to mass killings. “Anyone who, as president, describes asylum seekers at the U.S.-Mexico border as an infestation or an invasion … sows the kind of fear, the kind of reaction that we saw in El Paso,” the former Representative Beto O’Rourke of Texas said on CBS News’s Face the Nation.

In California in the late 19th century, immigrant Chinese laborers bore the brunt of the “invasion” discourse. While the term historically had been used to refer to the incursion of armed forces, Chinese immigrants were seen as “invaders” of a more insidious kind. In 1876, three years after the publication of The Chinese Invasion, a San Francisco lawyer named H. N. Clement testified at a California state Senate committee hearing that “the Chinese are coming” in the form of an “unarmed invasion.” As Erika Lee, the director of the Immigration History Research Center at the University of Minnesota, has detailed, the “invasion” alarms in California ended up drawing national attention, leading to Congress passing the Chinese Exclusion Act of 1882, the first significant law ever to ban an entire national group from entering the country.