"Even absent the pandemic, a June 1 deadline would be highly aggressive, and raises questions as to whether businesses have the information they need to adjust to the new rules and comply by that date," the senators wrote.

She is no stranger to difficult negotiations with the U.S., having played a central role in the 13-month effort to negotiate a replacement for NAFTA.

The long-awaited assessment the Liberals presented today says the new United States-Mexico-Canada Agreement is much better than letting the U.S. tear up the old NAFTA and put tariffs on Canadian steel, aluminum and automotive exports.

Alberta Premier Jason Kenney and Saskatchewan's Scott Moe say they see signs that tensions in their relationship with Ottawa are beginning to ease.

Deputy Prime Minister Chrystia Freeland will also be there for meetings with U.S. officials on the margins of the conference.

Trump signed the implementation bill, which cleared Congress two weeks ago, during a ceremony on the South Lawn of the White House.

The government will face two confidence votes this week over the throne speech and the new NAFTA.

"We’re not holding up this potential threat to bring down the government over NAFTA," says Mark Strahl.

Freeland has sent a letter to the leaders of the Conservatives, NDP, Bloc Quebecois and Greens on the eve of the return of the House of Commons asking for their support.

It would be rather disastrous for Canada to suddenly decide we’re not on board with the new NAFTA at this point, Rob Breakenridge says.