The most important adviser to President Trump in the trade negotiations with China that have captivated the global financial markets may be none other than Soviet dissident-turned-Israeli politician Natan Sharansky.

Whether Mr. Trump has sought Sharansky’s counsel directly I don’t know. What’s unmistakable, though, is that Mr. Trump increasingly has been voicing the approach Mr. Sharansky has long been advising — of linking American trade policy to human rights rather than treating the two as entirely unrelated.

On August 18, speaking to reporters at Morristown, N.J., Mr. Trump said Chinese violence against protesters in Hong Kong would make a trade deal with America more difficult. “I respect Congress. I respect the views of Congress. And I respect, most importantly, the views of the people of our country. And I think it would be much harder for me to sign a deal if he did something violent in Hong Kong,” Mr. Trump said.

The 2004 book “The Case For Democracy,” which Mr. Sharansky co-authored with the man who is now Israel’s ambassador to the United States, Ron Dermer, said, “The formula that triggered a democratic revolution in the Soviet Union had three components: People inside who yearned to be free, leaders outside who believed they could be, and policies that linked the free world’s relations with the USSR to the Soviet regime’s treatment of its own people. Whether this same formula is applied to a great power like China or a weak despotism like Zimbabwe, a secular totalitarian regime like North Korea or a religious tyranny like Iran makes no difference. It will work anywhere around the globe.”

The pioneer of this “linkage” idea was Henry “Scoop” Jackson, a Democratic Senator from Washington state. The Jackson-Vanik Amendment, signed into law in 1975, tied America’s trade policy toward the Soviet Union to the Soviet Union’s willingness to permit freedom of emigration.

As documented in the book by Messrs. Sharansky and Dermer, the New York Times hated the idea. “We do not believe it is productive to try to enforce political changes in the Soviet (or any other) system through the unilateral use of economic pressure. The results are likely to be the opposite of those intended,” the Times wrote in a 1972 editorial.

In 1974 the Times worried in another editorial that liberalization of the Soviet Union “is more likely to be prevented than accelerated by excessive outside pressure.” Even the Wall Street Journal, while a heroic foe of the Soviet Union in many other respects during the Cold War, gave the Jackson and Vanik approach about the same treatment it has lately been giving Peter Navarro and Mr. Trump on the China tariffs.

When the law was passed, Mr. Sharansky was trapped behind the Iron Curtain. He spent nine years in Soviet prisons as punishment for his activism and for wanting to escape Communism. In retrospect, Mr. Sharansky credits the law, and Jackson, for playing an important role in defeating the Soviet Union.

Historical causation is difficult to prove; it’s possible that the Soviet Union would have collapsed or reformed on its own without the American trade pressure. When one talks about this with Mr. Sharansky face to face, as I’ve been fortunate enough to do several times, one comes away informed that the effects on the Soviet economy were far from the only consequences of Jackson-Vanik.

As significant — perhaps even more significant — was the moral clarity and the inspiration that the Jackson-Vanik Amendment provided to people like Mr. Sharansky and his allies who were taking great personal risks. They knew that they had allies in America who cared about them and who were also willing to make certain sacrifices for the cause of advancing freedom.

President Trump has been putting trade pressure on Iran by pulling out of the nuclear deal entered into by President Obama, and he’s been putting trade pressure on China with tariffs. These moves have been denounced widely in the same elite American coastal precincts — think tanks, editorial pages — that once scorned Jackson-Vanik.

If Mr. Trump stands his ground the way Mr. Sharansky and Scoop Jackson did, the American tariffs will eventually come off China — but only after political freedom and democracy advance there, and not only in Hong Kong. It has the potential to turn the tariffs narrative into something bigger than two economies competing for national advantage. It changes the story from a struggle for manufacturing jobs into a fight for liberty.