As Donald Trump continues to surge in the polls, a staple of Trump’s campaign rhetoric remains his emphasis on bringing manufacturing jobs back to the United States and confronting foreign competitors like China and Mexico over their unfair trading practices.

For instance, in an interview with Sean Hannity Tuesday night Trump said:

We have to bring back our jobs back from China. As an example, we have to bring manufacturing back. You look at Japan with the boats that come in pouring in with cars—you know what we send Japan? We send them beef. We send them wheat, we send them corn…

Ok? I want American cars. If Japanese companies build here, that’s fine. But you know what? I don’t want to see boats pulling into Los Angeles because I saw boats the other day that were the biggest boats I’d ever seen—loaded up, you wouldn’t even believe the thing could float so many cars. And then you see these cars just [one after another] boom, boom. They’re not made here. How is that helping us? I don’t want cars made in Mexico. I love Mexico, I love the Mexican people… I have a great relationship with Mexico… [B]ut that doesn’t help us from the standpoint that their leaders are so much sharper, and I use the word cunning—they’re more cunning than our leaders…

They make cars in Mexico, and they just send them across the border. How does that help us?

Trade expert Clyde Prestowitz—who served as a trade negotiator for Ronald Reagan and Bill Clinton—has documented how other nations are outsmarting U.S. leaders on trade.

For instance, with regards to Trump’s example of Japan—Prestowitz writes that through its dealership structure, Japan has closed its market to U.S. car exports: “In Japan, however, the dealers are owned or controlled by the makers. They sell only the cars from a particular maker and do not represent any outsiders.”

By contrast, Prestowitz writes that, “by law, U.S. dealers are independent of the auto makers and are free to sell any brand they wish. Exporters to the United States thus find it easy quickly to achieve national distribution of their vehicles.”

Polling data shows that Trump’s message on trade will resonate across the American electorate but that Republican voters—in particular—are the group most skeptical of international trade deals.

A recent YouGov poll shows that Republican voters—at higher rates than Democrats—think that free-trade agreements make U.S. wages lower, have resulted in job losses, and have hurt their household. When asked whether free trade helps or slows down the economy, Republicans by nearly a two-to-one margin believed that it slows the economy down (42 percent vs. 22 percent).

A 2014 Pew Poll similarly found that Americans believe free-trade deals reduce wages rather than raise wages by more than a two-to-one margin (45 percent vs. 17 percent); they believe that free-trade deals destroy jobs rather than create them by nearly a three-to-one margin (55 percent vs. 20 percent).

Trade, like immigration, represents an area where Republican leaders and donors are in a state of deep disagreement with Republican voters.

For instance, Republican leadership made the passage of a global trade and governance pact one of its highest legislative priority. According to a senior Republican Senate aide speaking to Breitbart News, “Republican leadership has never pushed for anything harder or more aggressively in my entire Congressional career than to deliver 60 votes for Obamatrade.”

As Sen. Jeff Sessions (R-AL) wrote after the passage of the fast-track trade authority, “Washington broke arms and heads to get that 60th vote—not one to spare—to impose on the American people a plan which imperils their jobs, wages, and control over their own affairs. It is remarkable that so much energy has been expended on advancing the things Americans oppose, and preventing the things Americans want.”

Trump’s stance against globalist trade policies and his support for bringing back American manufacturing distinguishes him from other top-polling candidates in the Republican field.

For instance, none of the other candidates have made cracking down on foreign trade a top issue. In fact, the two candidates favored by Republican donors, Jeb Bush and Marco Rubio, have both embraced the global trade pact negotiated by President Obama and have expressed support for his larger trade agenda as a whole.

In a May 13th address to the Council on Foreign Relations, Rubio even said that the passage of Obama’s trade pact and fast-track authority was central to his foreign policy doctrine. “My foreign policy doctrine consists of three pillars,” Rubio said. Global trade deals, Rubio explained, represents “the second pillar” of his doctrine: “Millions of the best jobs in this century will depend on international trade. It is more important than ever that Congress give the president trade promotion authority so we can finalize the Trans-Pacific Partnership and the Transatlantic Trade and Investment Partnership.”

In addition to declaring that global trade was one of the three pillars of his foreign policy doctrine, Rubio also argued that global trade was one of three pillars to his Asia policy in particular. As he wrote in an op-ed earlier this year that appeared in the Wall Street Journal: “There are three pillars to an Asia policy for a new American century… The U.S.-Japan alliance is at the center of all three pillars.”

The fast-track procedure to expedite the deals such as the Trans-Pacific Partnership (TPP) and the Trade in Services Agreement (TiSA), which would expand immigration and foreign worker programs, passed the Senate with 60 votes—meaning that if even one vote switched, the measure would have failed. Rubio, having endorsed the bill, was of course one of the 60 votes. However, as Breitbart News has investigated, Rubio has yet to provide any specific evidence that he actually read the deal.

Rubio’s position on trade is supported by publications like the Wall Street Journal and commentators like George Will, who have all strongly backed so-called free-trade policies, which Donald Trump has argued would hollow out the middle class.

So far, in the first Fox News Republican debate, though a number of candidates on stage disagreed with Trump on trade, none of them raised it as an issue—suggesting that they might be familiar with the polling data that shows open door trade policies are a tough sell to Republican voters.