GWEN IFILL: But, first: If immigration is one of this year's big policy debates, the other is free trade. And when it comes to the future of how the U.S. does business abroad, the two major candidates are not sounding that far apart.

Last week, correspondent Paul Solman spoke with economist Peter Navarro about Donald Trump's approach.

Tonight, Paul talks trade with Ohio Senator Sherrod Brown, one of Hillary Clinton's biggest supporters.

It's part of our Making Sense series, which airs every Thursday.

SEN. SHERROD BROWN (D-Ohio): Denise? Denise.

PAUL SOLMAN: Sherrod Brown's been buying suits made in Brooklyn, Ohio, for years. The Democratic senator has long pushed made in America, long fought free trade agreements which, he says, have shafted blue-collar workers.

MAN: Senator Brown is calling for action against cheating China.

SEN. SHERROD BROWN: They don't play fair, and we have got to fight back.

PAUL SOLMAN: The message carried him to reelection four years ago in a state that's bled some 300,000 manufacturing jobs in the last 20 years.

SEN. BERNIE SANDERS (I-Vt): We have lost millions of decent-paying jobs. That has got to end.

PAUL SOLMAN: Left-wingers like Bernie Sanders have long shared Brown's stance on trade. But opposition to trade deals has gone mainstream in 2016.

DONALD TRUMP (R), Presidential Nominee: We're letting our jobs go to Mexico.

HILLARY CLINTON (D), Presidential Nominee: As president, I will stand up to China and anyone else who tries to take advantage of American workers and companies.

PAUL SOLMAN: The big switch is Clinton, long associated with free trade agreements. Brown threw his support behind her early on, because, her insists, she now gets it.

SEN. SHERROD BROWN: She is someone who understands trade, who understands we want more of it, but we want it under a different set of rules.

PAUL SOLMAN: Brown brought us to the Keystone suit plant in the Cleveland suburbs to elaborate.

SEN. SHERROD BROWN: What she wants to do on enforcing trade policy, she wants to triple the number of trade enforcement officers, which will really matter in trying to level the playing field fighting with South Korea and China and other countries that don't play it straight.

She wants a special trade prosecutor directed specifically at China, where we have by far our largest bilateral trade deficit. We lost five million jobs from 2000 to 2010, 60,000 plants closed — this one almost closed — in large part because of unfair trade practices.

PAUL SOLMAN: Two years ago, Hugo Boss it would close this factory. But Brown helped facilitate its sale to Keystone Tailored Manufacturing.

The workers here have been making Hart Schaffner Marx suits ever since.

SEN. SHERROD BROWN: You know, these are not high-paying jobs, but they're good union jobs with good union benefits.

PAUL SOLMAN: No surprise, then, that the senior senator is something of a hero here. Brown says he walks the walk on trade, while Donald Trump doesn't.

SEN. SHERROD BROWN: I have a number of suits that were made in — on this shop floor. Donald Trump outsources his suits to Mexico. He could have bought them here. He could have had them made here. He outsourced — outsources his ties to China. He outsources. This tie's made in the U.S.

Donald Trump talks a good game on trade, but he's never lived it. He's lined his pockets by outsourcing jobs to low-wage countries, and now he's talking about trade as if he actually means it? I have been engaged in this fight for 25 years against bad trade policy, I have never seen Donald Trump stand with us. I have never even heard Donald Trump's name or voice while we're working against bad trade policy.

PAUL SOLMAN: Well, you haven't heard Hillary Clinton's voice on this issue either.

SEN. SHERROD BROWN: I absolutely trust Hillary Clinton to stand strong on these trade agreements. When she was in the Senate, she voted against some, she voted for some.

PAUL SOLMAN: Clinton has taken plenty of heat for changing her mind about the Trans-Pacific Partnership. As secretary of state, she said:

HILLARY CLINTON: This TPP sets the gold standard in trade agreements.

PAUL SOLMAN: But candidate Clinton has reversed course.

HILLARY CLINTON: I will stop any trade deal that kills jobs or holds down wages, including the Trans-Pacific Partnership.

HILLARY CLINTON: I oppose it now, I will oppose it after the election, and I will oppose it as president.

PAUL SOLMAN: You understand why people would say she's absolutely done an about-face on this issue, right, and that she might well go back on the position she now has if she becomes president.

SEN. SHERROD BROWN: Well, she supported TPP in the early days because she was the — she worked for the president of the United States in his cabinet, and so did everybody else in the Cabinet support TPP.

As a candidate, she understands it, and she looks at TPP in a different way, fixing rules of origin, fixing currency issues, fixing investor-state dispute settlement, which undermines environmental and worker safety standards.

PAUL SOLMAN: In nearby Cleveland, at the former site of
Premier Manufacturing, we met economist Susan Helper, a progressive Democrat who also supports Hillary Clinton.

So, when a plant like this closes down, there's substantial economic damage.

SUSAN HELPER, Economist: yes. The people in the plant lose their jobs. People working in restaurants nearby lose their jobs. Home values fall, et cetera.

PAUL SOLMAN: This steel wire plant, which moved most of its work to Mexico, exemplifies the migration of U.S. manufacturing.

SUSAN HELPER: The decline of unions and the figuring out by management of strategies to avoid unions in the U.S., and then a movement, particularly after NAFTA was signed, to Mexico, and even lower wages there.

PAUL SOLMAN: The North American Free Trade Agreement was signed by Bill Clinton in 1993. But his wife has become a critic, for good reason, says Professor Helper.

SUSAN HELPER: I think that one of the things now, we have greater experience. We can see what — what's happened as a result of some of the trade agreements.

There's some very excellent work that suggests that workers who are displaced by trade or other reasons, but particularly by trade, don't easily find new jobs. And particularly in the case of a lost manufacturing job, the new job that somebody gets doesn't equal their previous wage.

PAUL SOLMAN: But many economists argue, robots, not trade deals, are the real job-robbers.

So, I asked Sherrod Brown, isn't it technology that's actually replacing jobs, as opposed to unfair trade?

SEN. SHERROD BROWN: Well, it's all of the above. It's unfair trade practices. It's technology. About five miles from my home is a company called ArcelorMittal. That plant was the first plant in world history where close to one person hour of labor produces one ton of steel.

That's technology, that's efficiency. That's put some steelworkers out of work because they're so efficient.

PAUL SOLMAN: Right.

SEN. SHERROD BROWN: But unfair trade practices has also — have also put a lot of those workers out of work.

PAUL SOLMAN: Moreover, Susan Helper's research suggests that technology can actually add jobs at ArcelorMittal or anywhere else.

SUSAN HELPER: When your productivity goes up, your price falls, so more people are going to want to buy things made out of steel. We looked at manufacturing industries over the last couple of decades, and found that those industries that had the greatest productivity growth actually had the most job gains.

PAUL SOLMAN: But why?

SUSAN HELPER: Because they found new markets. They were able to expand into new markets and find new uses for the technology that they had innovated.

PAUL SOLMAN: Even so, Sherrod Brown believes candidate Clinton's tougher stance on trade is a welcome one.

SEN. SHERROD BROWN: I'm glad we are most efficient steel plant in the world less than 10 miles from here, but we have got a lot of work to do to make sure trade enforcement is done the way Secretary Clinton wants it done. And that — that will ultimately provide jobs. It will save jobs. It will help manufacturing rebirth.

PAUL SOLMAN: This is economics correspondent Paul Solman in and around Cleveland, Ohio.