New York (CNN) Amid market turmoil over the status of President Donald Trump's trade deal with the Chinese, many American businesses are focused on a different threat: his promise to unilaterally cancel the North American Free Trade Agreement.

Trump said on his way home from Argentina that he would give Congress a choice between his US-Mexico-Canada Agreement or USMCA, or none at all.

Killing the 1994 trade deal without a successor in place would invite Mexico and Canada -- both leading importers of US goods -- to put tariffs on items coming from the United States, risking a severe economic shock.

"We have continuously told the administration throughout the USMCA process that it is essential for the new agreement to be implemented seamlessly, so that our businesses can learn the new rules and have time to adjust our supply chains to take advantage of the deal," said Rick Helfenbein, president of the American Apparel and Footwear Association. "Adding additional pressure on Congress to sign or fail is not in the best interest of America."

Top White House advisers have been saying for months that they're confident Democrats will approve the USMCA.

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