KANSAS CITY, Mo. — Donald Trump’s aggressive rhetoric on illegal immigration has obscured a potentially historic policy shift — the Republican presidential nominee is the first major party candidate in modern memory to propose limiting legal immigration.

In his speech on immigration Wednesday night, Trump capped a list of steps to combat illegal immigration, with a final pledge to completely revamp the country’s legal immigration system in order to lessen the number of people allowed into the United States. “We will reform legal immigration to serve the best interests of America and its workers, the forgotten people,” Trump said. “Workers. We’re going to take care of our workers.”

Trump talked about limiting immigration to its historic norms. The share of foreign-born people in the United States — 13 percent of the population — is at its highest level since 1920. By making the case in a nationally televised address that immigration overall has to be limited, Trump has embraced the ideals of a small group of activists who, for decades, have sought to sharply reduce all forms of migration to the United States.

“It’s a big change,” said one of those activists, Roy Beck, president of Numbers USA, who argued that Trump can espouse ideas that previous politicians, dependent on campaign contributions from business, cannot. “The politicians who are major speakers on this have always focused on rule of law.”

Since the 1990s, politicians who have taken a tough stance on immigration have usually come out against amnesty for anyone living in the country illegally, but spoke favorably of legal immigration. Many business groups that traditionally support the GOP seek higher levels of legal immigration. Advocates say the push underscores how necessary migration is for the economy, while critics contend it pushes wages down.

“For Trump, it’s ‘I’m all against immigration, legal or otherwise, full stop’ — which is a massive departure for the Republican party,” said Ali Noorani of the National Immigration Forum Action Fund. “He wants to turn around the demographic trends of the country and return the United States to a majority white country.”

It’s also a stark contrast with Democrat Hillary Clinton, who wants to expand President Barack Obama’s order deferring deportation for many in the country illegally and supports measures that would expand legal immigration.

The demographic transformation by legal immigration dwarfs that resulting from illegal entry. The U.S. Census estimates that whites will be a minority in about 30 years, with the number of immigrants on the rise.

The upswing in immigration started in 1965 with the removal of racially based immigration quotas that favored immigration from European countries over the rest of the world. Some 42 million people currently live in the U.S. who emigrated from other countries. An estimated 11 million of them are here illegally.

Those who want to limit migration say the concern is economic, not racial. Though most economists believe immigration is a net benefit to the economy, opponents argue it disproportionately hurts blue-collar workers by lowering wages. Immigration restrictionists note that this used to be a bipartisan position. They point to a 1995 commission chaired by former Rep. Barbara Jordan, a prominent black liberal Democrat, that called for limiting immigration to protect U.S. workers.

Mark Krikorian of the Center for Immigration Studies argued that discussing appropriate levels of overall immigration, rather than focusing on people breaking the law to stay in the country, can defuse racial tension around the issue.

“In the right hands it can drain the issue of some of its vitriol — it has nothing to do with whether you’re Mexican or Ukrainian,” Krikorian said. “It’s about the numbers.”

Trump did not get into the details of how he would restrict legal immigration Wednesday night, instead calling for a commission the revamp the nation’s immigration laws and sunsetting visa provisions. Some of his proposals, like changing the immigration system to focus more on high-skilled laborers, are similar to ideas in a 2013 immigration bill that stalled in Congress because it would let many of the 11 millions people in the country illegally remain here.

But others are a sharp departure. Trump said he’d oppose allowing in immigrants from countries with a history of terrorism and, on his campaign website, he calls for companies to hire unemployed Americans before importing foreign workers on visas.

Todd Schulte of FWD.us, a pro-immigration group founded by Mark Zuckerberg and Bill Gates, said those hiring provisions were designed to make immigration impossible. “The level of bureaucracy that goes into that in a fast-moving global economy — you are cutting off these companies’ ability to hire and grow,” Schulte said. “He’s preying on this zero-sum mentality that there’s a fixed number of jobs here. That’s completely false.”

Doris Meissner, the former commissioner of the Immigration and Naturalization Service, said that Trump’s proposal to limit immigration is in line with a theory that after bursts of immigration the country should limit migration. But she noted that the global economy has been transformed and that if the country doesn’t let more people in legally, they may arrive illegally instead.

“It has to be a regulated system that reflects the market,” Meissner said. “Otherwise, it’s prohibition — and you remember how that worked out.”