The differing world views of Hillary Clinton, the globetrotting former U.S. secretary of state, and Donald Trump, who preaches "America First," are on display on the issue of trade.

Trump blames trade deals and China's inclusion in the World Trade Organization — negotiated during the presidency of Clinton's husband — for the closings of U.S. factories and the loss of millions of American jobs.

Clinton, who faced another free trade critic, Sen. Bernie Sanders, during the Democratic primaries, has tried to soften her past support for trade deals.

Q: How did we get here?

A: The merits of free trade have come under attack in recent years as attention focused on the workers and communities that critics say have been hurt by the global movement of capital and jobs. A bipartisan coalition of politicians, unions, religious groups, Internet freedom activists and conservationists opposes a new generation of proposed trade deals, including the Asia-focused Trans-Pacific Partnership. Unless President Barack Obama manages to win congressional approval of the TPP this year, the treaty's future will be up to the next president.

Q: How pro-free trade is Clinton?

A: Trump, like Sanders before him, paints Clinton as a dyed-in-the-wool free trader. Her record is a bit more nuanced. "From 1993 to 2016, she supported eight deals, opposed two, flip-flopped from opposing to supporting three, and flip-flopped the other way on two others," according to PolitiFact. In 2007, during her first run for the presidency, Clinton called NAFTA, which her husband signed, "a mistake to the extent that it did not deliver on what we had hoped it would." After voicing support for the TPP, Clinton came out against it in 2015.

Q: How anti-free trade is Trump?

A: Unlike Clinton, Trump has never had to vote on a trade deal, and his running mate, Indiana Gov. Mike Pence, has a long record of supporting such deals.

"I'm not against trade," Trump has said. "I just want to make better deals."

He promises to pull the U.S. from NAFTA if Canada and Mexico refuse to renegotiate it. He called the TPP "a rape of our country." He says he would impose punitive tariffs on goods from China, which doesn't have a free-trade deal with the U.S. but is a member of WTO. And if WTO rules block such tariffs, Trump says he would consider pulling the U.S. from the trade group altogether.

Inconveniently for him, some of his personally branded products, such as Donald J. Trump dress shirts and perfume, are made in Bangladesh, China, Honduras and other low-wage countries.

Q: What do polls say?

A: It depends on how the question is asked. A Bloomberg Politics poll in March showed that 65 percent of Americans want U.S. trade policy to "have more restrictions on imported foreign goods to protect American jobs." But in a Wall Street Journal/NBC News poll this month, 55 percent said free trade with other countries is a good thing because it opens up new markets.

A March poll by the Pew Research Center found that 67 percent of Trump supporters view free trade agreements as a bad thing, and 58 percent of Clinton supporters say they are a good thing.

Q: Why does this matter?

A: Trump's case against global trade is at the core of his appeal to white working-class men. Their support could help him win crucial U.S. Rust Belt states — including Pennsylvania, Ohio and Michigan — that are home to the once-vibrant U.S. manufacturing sector.