The quest to renew NAFTA is slowing to a crawl as Canada and Mexico tiptoe around America's most controversial proposals, throwing into doubt the three nations' ability to reach a quick deal.

The U.S. is frustrated with the reluctance of Canada and Mexico to present counter-proposals on key issues such as regional content rules for cars, which could make or break a deal. Mexico and Canada continue to portray key U.S. demands as unworkable, and are holding out hope the Trump administration will bow to pressure from U.S. lawmakers and corporations to keep core elements of the deal alive.

There has been an air of technocratic calm to the talks this week in Mexico City as bureaucrats plug away at less explosive issues. Trade chiefs from the three countries aren't attending this round, which has dialed down rhetoric on the ground, but also left a political void for overcoming some of the sticking points. The sprint for a U.S. tax overhaul this year has overtaken the agenda in Washington, diverting some attention from NAFTA.