Washington, Sept. 4 -- US President Donald Trump has said that America will have to "unwind" trade deals it had reached with the European Union, Japan, South Korea, and others if the country's Supreme Court rules the global tariffs illegal, and he warned that a loss in the court could cause the United States "to suffer so greatly."

He told reporters in the Oval Office that duties gave him leverage to strike deals with major trading partners across the world that saw America levying import duties on their products without any reasonable retaliation. This arrangement, Trump said, has given the United States "a chance to be unbelievably rich again."

While speaking to reporters at the White House, Trump said he would ask the Supreme Court t...