Delegates from the United States, Canada and Mexico are meeting in Arlington, Virginia, this week for a fourth round to try to revise the 23-year-old North American Free Trade Agreement (Nafta), which allows tariff-free trade across the three borders.
But analysts say the negotiations seem headed for the rocks, with US proposals unpalatable to Mexico and Canada. US President Donald Trump has said the pact has cost American jobs.
Chief among the tough US proposals is a "sunset" provision that would force renegotiation of the trade pact every five years - undermining long-term business plans.
The US' other trade partners, including those in Asia, are nervously watching the Nafta talks, which could have implications for supply chains and movement of products, services and people, analysts say.
SEE TOP OF THE NEWS: Talks to overhaul Nafta at risk of failure: Experts