Trade barriers

FILE - This Oct. 8, 2014, file photo shows a Wall Street address carved in the side of a building, in New York. The U.S. stock market opens at 9:30 a.m. EST on Friday, March 9, 2018. (AP Photo/Mark Lennihan, File)

President Donald Trump, center, speaks in the Roosevelt Room of the White House in Washington, Thursday, March 8, 2018, before signing two proclamations, one on steel imports and one on aluminum imports. Standing with Trump are workers, left, Vice President Mike Pence, Treasury Secretary Steven Mnuchin and Commerce Secretary Wilbur Ross. (AP Photo/Susan Walsh)

People walk past an electronic stock board showing Japan's Nikkei 225 index at a securities firm in Tokyo Friday, March 9, 2018. Asian shares were mostly higher Friday on relief that President Donald Trump's tariffs on U.S. steel and aluminum imports may not be as harsh as initially feared. News Trump and North Korea's leader will meet also lifted sentiment.(AP Photo/Eugene Hoshiko)

European Commissioner for Trade Cecilia Malmstroem speaks during a media conference at EU headquarters in Brussels on Wednesday, March 7, 2018. The European Union will set out its strategy Wednesday on how to counter potential U.S. punitive tariffs on steel and aluminum. (AP Photo/Virginia Mayo)

Vice President Mike Pence, right, listens as President Donald Trump speaks in the Roosevelt Room at the White House in Washington, Thursday, March 8, 2018, during an event where Trump signed two proclamations, one on steel imports and the other on aluminum imports. (AP Photo/Susan Walsh)

FILE - In this Feb. 23, 2018, file photo, Treasury Secretary Steve Mnuchin gestures as he answers questions during a briefing at the White House in Washington. It looks like President Donald Trump’s romance with the Goldman Sachs crowd is going cold. Top economic adviser Gary Cohn is only the latest Goldman figure to head for the White House exits. Cohn is the fourth high-profile Goldman alumni to leave the administration. That makes Mnuchin the last Goldman veteran in a top administration job. (AP Photo/Pablo Martinez Monsivais, File)

In this March 5, 2018 photo, a worker manipulates coils of steel at Xiwang Special Steel in Zouping County in eastern China's Shandong province. China says it "firmly opposes" U.S. President Donald Trump's tariff increase for imported steel and aluminum but gave no indication whether Beijing might impose its own measures in response. (Chinatopix via AP)

President Donald Trump reaches out to shake the hand of Dusty Stevens, a superintendent at Century Aluminum Potline, during an event in the Roosevelt Room of the White House in Washington, Thursday, March 8, 2018. Trump signed two proclamations, one on steel imports and the other on aluminum imports. (AP Photo/Susan Walsh)

FILE - In this Oct. 8, 2014, file photo, American flags fly in front of the New York Stock Exchange. The U.S. stock market opens at 9:30 a.m. EST on Thursday, March 8, 2018. (AP Photo/Mark Lennihan, File)

Peru's Trade Minister Eduardo Ferreyros, left, Secretary of Economy of Mexico Idelfonso Guajardo, center, and Japan's Trans-Pacific Partnership minister Toshimitsu Motegi talk during the signing ceremony of the Comprehensive and Progressive Agreement for the Trans-Pacific Partnership, TPP in Santiago, Chile, Thursday, March 8, 2018. (AP Photo/Esteban Felix)