There is no evidence that Mr. Trump’s Facebook ads directly influenced the author of the manifesto, who wrote that his views “predate Trump” and posted the document on 8chan, an online forum known as a haven for extremists. But Mr. Trump, through his speeches, tweets and campaign ads, has elevated the idea of an “invasion,” once a fringe view often espoused by white nationalists, into the public discourse.
Some other Republican candidates have echoed Mr. Trump’s language in their own ads. “Let’s call this what it is — an invasion of our country,” read a recent Facebook ad for Tommy Tuberville, a former Auburn football coach who is running for Senate in Alabama. Other Republicans who have used the word “invasion” in Facebook ads include a candidate for governor in West Virginia and a candidate for Senate in North Carolina.
The cognitive linguist George Lakoff said the word “invasion” was a potent one for Mr. Trump to use because of what it allowed him to communicate. “If you’re invaded, you’re invaded by an enemy,” he said. “An invasion says that you can be taken over inside your own country and harmed, and that you can be ruled by people from the outside.”
Mr. Lakoff added: “When he’s saying ‘invasion,’ he’s saying all of those things. But they’re unconscious. They’re automatic. They’re built into the word ‘invasion.’”
For the writer of the manifesto, the concept of an “invasion” had an additional, racist meaning: He promoted a conspiracy theory called “the great replacement,” which claims that an effort is underway to replace white people with nonwhite people.
Democratic candidates for president blamed Mr. Trump for helping spread such views. “White supremacy is not a mental illness,” Senator Elizabeth Warren of Massachusetts said on Monday. “We need to call it what it is: Domestic terrorism. And we need to call out Donald Trump for amplifying these deadly ideologies.”
But the radio host Rush Limbaugh attacked Democrats and the news media on Monday for pointing the finger at conservatives like him. “We’re sick and tired, every time this happens, people that we believe in being blamed for it,” he said. “We’re sick of it. None of us pulled the trigger, none of us want these things to happen, and yet we turn on the media and that’s what we hear.”