Donald Trump is staring down decades of Republican Party orthodoxy on a signature issue
Donald Trump
Donald Trump

(Donald Trump.Jeff Swensen/Getty Images)

Donald Trump has launched an all-out assault on America's free-trade agreements, hitting a peak in his antitrade message that has swept him through the primary season and into the general election.

And in doing so, he is breaking with decades of Republican orthodoxy, staring down party leaders and some of their top messengers over an issue that has helped define the GOP.

During a speech titled "Declaring American Economic Independence" last week, Trump called for pulling out of the North American Free Trade Agreement and for Congress to refuse to ratify the landmark Trans-Pacific Partnership. He also demanded that presumptive Democratic nominee Hillary Clinton pledge to withdraw from TPP on her first day in office, should she be elected.

During his speech, given just outside Pittsburgh on Tuesday, Trump called Nafta the "greatest jobs theft in history." He later said during a rally in southeast Ohio that night that TPP was "another disaster done and pushed by special interests who just want to rape our country."

"A continuing rape of our country," he said. "That's what it is, too. It's a harsh word. It's a rape of our country."

Trump's tough stance on trade aligns him much closer with the liberal left than it does with the traditional Republicans. As Trump was blasting trade in a series of speeches and events this week, Sen. Bernie Sanders of Vermont called for ensuring that TPP doesn't get a vote before Congress. Even Clinton, the candidate most aligned with the Obama administration, having served in it as secretary of state, has come out against TPP as it's currently structured.

"Democrats must do all they can to defeat the TPP. #StopTPP," Sanders wrote in a tweet.

But no one's antitrade message has been as hard-line as that of Trump, who places the blame for economic hardships at home squarely on increased globalization.

Donald Trump
Donald Trump

(Jeff Swensen/Getty Images)

GOP Sen. Jeff Flake of Arizona, a fierce critic of Trump, told Business Insider in an interview last week that he thought the Manhattan billionaire's message of "economic independence" was simply a code for "Fortress America."

"Anybody who believes that we're going to grow economically and deal with the huge fiscal problems that we have from shutting ourselves off from the rest of the world is just certainly not what I'd call a Republican," Flake said. "I mean we believe in free trade. We still do. Nafta is not a dirty word."

Trump, whose clothing line is produced overseas, has made an antitrade argument that is "easier to identify," Flake said. He added that focusing only on the image of people who have lost their jobs because a factory closed or relocated oversimplified the issue.