The Trump administration has taken an early step in renegotiating the North American Free Trade Agreement, sending the U.S. Congress a draft list of priorities for the negotiation that expresses hope for change in a broad range of areas.

In a draft letter sent to Congress, Stephen Vaughn, the acting U.S. trade representative, details the administration’s ambition to redraw the 23-year-old trade deal in a way that delivers “timely and substantial” results for U.S. workers and consumers.

The letter includes vague references to making changes in a number of areas, including agriculture, government procurement, tax policy, intellectual property, rules of origin for things like car parts, telecommunications and dispute resolution. It also suggests a mechanism to impose tariffs if imports flood in and threaten U.S. industry.

But in a potentially worrisome note for both Canada and Mexico, Vaughn says that the “persistent U.S. deficit” in the trade of goods “demands that this administration take swift action to revise the relationship to reflect and respond to the new 21st century challenges.”

Asked about the letter Thursday, Prime Minister Justin Trudeau said that Ottawa would work “constructively” with the Trump administration to “draw out even more benefits from this close working relationship.” But the prime minister echoed past warnings that any protectionist moves by Washington risk damaging America’s economic interests.