“It’s a conspiracy theory that began on a tiny hate group on the Arizona that has spread far and wide and quite deeply penetrated the mainstream,” said Potok.

In 2014, a video circulated of a man who described himself as a former Border Patrol agent, who charged that the influx of refugee children was an act of “asymmetrical warfare” carried out by unnamed malignant forces so that they could sneak in drugs and chemical and biological weapons (he also put suggested that the Ebola outbreak in Africa was spread by intentional conspiracy). The video was cited by right-wing figures including former Congressman Allen West.

Others, including former Texas Gov. Rick Perry, accused the U.S. government of being complicit in coordinating the wave of Central American child refugees. That taps into the notion, said Potok, that President Obama wants immigrants and refugees to come to the United States because they will be future Democratic voters. It’s also part of a broader theory that dangerous forces abroad are allied with an internal fifth column of liberals who are aiding the enemy for their own nefarious purposes.

These sorts of conspiracies are not limited to immigration: the far right that has taken over the Republican Party incorporates a whole range of extreme theories rooted in the Cold War paranoia of the John Birch Society (which believed that the civil rights movement was a communist plot and more recently mainstreamed the notion that the United Nations was scheming to destroy the American way of life in the name of environmentalism) and the rantings of Alex Jones and his Infowars empire.

Trump makes a similar but even more sinister argument when he suggests that President Obama is resettling Syrian refugees because he is being fooled by a conspiracy to attack America or may be complicit in it. “Why is he so emphatic on not solving the problem?” Trump asked. “There’s something we don’t know about. There’s something we don’t know about.”

Trump’s position on free trade likewise reflects this worldview. While he does argue that global trade is organized to advantage elites at the expense of workers—echoing criticisms that are also common on the left—the centerpiece of his plan for trade is to “appoint the toughest and smartest trade negotiators to fight on behalf of American workers.”

American leaders have simply been crappy negotiators, he contends. And he will be a much, much better one.

“The most important component of our China policy is leadership and strength at the negotiating table,” according to his website.

There are (to oversimplify matters) two basic radical critiques of the way the world works. One is left-wing and systematic. It takes account of various roles played by different classes and groupings in large economic and political processes. Trump subscribes to the other framework, a form of conspiracist thinking long popular on the far right: contemporary economic problems are created by small cliques in smoky rooms rather than by the fact that labor’s bargaining power against business has been undercut across the board.

This worldview offers another possible explanation as to why Trump went to Mexico to meet with President Enrique Peña Nieto on Wednesday. It was an opportunity not only for Trump to look presidential but also to present himself as the savvy negotiator that is at the core of his personal brand. Perhaps he not only asked Peña to build the wall, but to stop sending his people here as well.

The reality, of course, is that Mexico doesn’t decide which immigrants come to the United States; immigrants experiencing complex social and economic realities do. But conspiratorial explanations become increasingly appealing as the global forces that shape people’s lives become ever more abstract. Trump isn’t just tapping into racist sentiment. He’s channeling a right-wing account of how the world works that is no longer relegated to the fringe.