After China unveiled steep retaliatory tariffs on American exports on Wednesday, Treasury Secretary Scott Bessent issued a sharp and somewhat surprising response: “So what?”

The question underscored the Trump administration’s argument that America has the upper hand in a trade war with China given how reliant its economy is on exports to the United States.

The United States buys far more goods from China than China buys from the United States. But Beijing’s decision to retaliate against President Trump’s punishing tariffs by raising levies on American imports to 84 percent could sting more than Mr. Bessent let on.

“American companies that have been selling to China, and have been enormously successful doing that, are not going to be able to do that because of Chinese retaliation,” Sean Stein, the president of the U.S.-China Business Council, said in the hours before Mr. Trump ratcheted up his tariffs again.

“Tariffs on the Chinese side and the U.S. side cover everything,” Mr. Stein added, meaning everything from aviation to medical imaging to agriculture would be affected and “trade is going to slow,” he said.