Competing visions of world trade are set to collide at the Group of 20 summit of world leaders in Hamburg, Germany, this week.

U.S. President Donald Trump's "America First" approach faces off against the European Union and its support for broad free trade agreements, with the Europeans touting a new, far-reaching pact it is completing with Japan.

The summit takes place with the global economy in fairly good shape; the International Monetary Fund sees growth rising from 3.1 percent last year to 3.5 percent this year and 3.6 percent in 2018. But trade among countries has not recovered to the levels from before the global financial crisis.

Increasing trade is credited by economists for raising global growth and prosperity over the past decades. Its benefits, however, have been unevenly distributed among workers and industries.

Here's what's on the table when the big shots sit down together on Friday.

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U.S. VERSUS THE WORLD?

Trump's views on trade will put him at odds with most other major leaders.

He says free trade deals that enable goods to pass borders without import taxes or regulatory hurdles have hurt American companies and workers. He is particularly focused on countries that sell more to the U.S. than they buy from American companies. At the G-20, those include China, Japan, and Germany.

The summit's host, German Chancellor Angela Merkel, said recently that "anyone who thinks that they can solve the problems of this world with isolationism and protectionism is making an enormous mistake."

The European Union is expected to underline that approach by announcing the outlines of a free trade agreement with Japan on Thursday. The EU also recently completed a trade deal with Canada, whereas Trump pulled the U.S. out of an Asian pact.

"In my view it will be 19 against one at the G-20, and the European Union will try to take over the role of the U.S. in respect to trade," said Claudia Schmucker, head of the program on globalization at the German Council on Foreign Relations.

The 28-country EU had been discussing the deal with Japan for four years, but the timing of the announcement is symbolic.

"It's a direct answer to what Trump stands for," Schmucker said.

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STEELING FOR CONFLICT

The Trump administration has other countries on edge about one trade issue in particular: steel.

The U.S. government is investigating the possibility of putting new barriers on steel imports based on national security considerations.

The investigation's primary justification was China, which has flooded international markets with cheap exports, lowering prices and hurting steelmakers in other countries. U.S. import taxes imposed as a countermeasure have already sharply reduced Chinese steel imports. So those hardest hit by new barriers could potentially be countries like Canada, Brazil, South Korea, Mexico, and EU producers.

If the U.S. acts based on the rarely used national security exemption, other countries could follow suit, said Jeffrey J. Schott, senior fellow at the Peterson Institute for International Economics.

"There's a lot of uncertainty about what is going to be done, because the administration is fighting among themselves," said Schott. "They realized that there are countries that don't want to be sideswiped by U.S. actions."

A French official said that "if some measures had to concern European exports, we would obviously react very quickly, and we are getting prepared." He spoke only on condition of anonymity to brief reporters on the summit.

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READ THE FINE PRINT

Trump is likely to spar with other countries over how strongly to support free trade in the final statement representing what everyone agrees on. The statement, while non-binding, helps set the tone for global policy.

The previous G-20 statement from 2016 to avoid "protectionism in trade and investment in all its forms" was replaced at a smaller G-7 meeting this year with an emphasis on trade that's "free, fair and mutually beneficial."

It should be noted that countries haven't always lived up to that free-trade commitment. Yet the statement's language is relevant, argued analyst Schmucker from the German Council on Foreign Relations.

"To have at least a common understanding in favor of free trade is something valuable," she said.

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TIT FOR TAT

So has it come to a trade war? No. The Center for Economic Policy Research says in a trade report for the first six months of the year that G-20 protectionist measures aimed at the U.S. actually diminished during the period, while U.S. trade policy moved in favor of domestic firms.

That's not necessarily a win for Trump, says Manfred Elsig, professor of international relations at the University of Bern's World Trade Institute. "The other countries have so far not started to retaliate," he said. "I think the Trump administration would probably look at the data and say, 'we are on the right path.'"

"My reading of the data is different," said Elsig. "Everyone is watching and waiting. Once they are significantly hit by this protectionist agenda, they will start retaliating. And that is a place that no one wants to be."