Several of the states Trump carried in the 2016 election would be hit hardest by tariff retaliations from major U.S. trade partners. In Tennessee, where Trump won 61 percent of the vote, some $1.4 billion in exports could be at risk. Tennessee sends $202 million worth of auto exports to China that could be hit by tariffs, according to the Chamber’s data. It also sends $466 million worth of whiskey exports to Europe.

The Chamber, with some 3 million members, has worked closely with Republican presidents and had praised Trump for signing steep corporate tax cuts in December. But mounting trade tensions have opened a rift with the president. The group is expected to spend millions of dollars on the midterm elections this year in an effort to help elect candidates who back free trade, immigration and reduced taxes.

European Union warned Monday that a U.S. threat to slap import tariffs on cars and car parts would likely bring further retaliation from its trading partners on $294 billion of American made cars and auto parts.

That could hurt South Carolina, where $3 billion of the state's exports could be subject to retaliatory tariffs. South Carolina sends $1.9 billion worth of autos to China, according to the Chamber’s data.

Trump’s tough stance on trade with China appears to be having little impact on U.S. imports of goods from the world’s second largest economy, as consumer spending by American households remains strong amid historically low levels of unemployment. China’s customs agency said Monday that its exports to the U.S. were up 5.4 percent in the first half of this year and rose 3.8 percent in June.