The Canada-U.S. relationship will endure despite any possible friction between the two governments, Prime Minister Justin Trudeau said as he faces a looming deadline in trade talks.
"We're running out of time", Mr. Lighthizer said. "We certainly want to have an agreement with Canada".
Trudeau appeared on the panel alongside Foreign Minister Chrystia Freeland, who is leading NAFTA talks. Under U.S. trade law, the administration is required to submit to Congress a finalized, written agreement 60 days before it intends to sign it.
Mr. Lighthizer also suggested that Canada and Mexico can not expect swift relief on steel and aluminium tariffs, which the USA imposed on its NAFTA partners in June.
She declined to specifically discuss issues but signaled that Canada is continuing to press to preserve some form of anti-dumping and countervailing duty panels, now allowed under NAFTA's Chapter 19. "Hopefully we'll end up with something with Canada".
The U.S. has been holding negotiations with Canada after reaching a trade agreement with Mexico in August. If not, we'll have to do it in a separate deal as soon afterwards as we can. If Canada comes along now, that would be the best.
Lighthizer's comments on the state of the North American Free Trade Agreement negotiations were similar to those offered on condition of anonymity by Canadian and American officials.
Whether the US could actually proceed with a separate bilateral deal with Mexico, absent Canada, is a matter of debate.
Washington and Mexico City last month announced agreement on a new trade pact, but a separate track of intensive talks with Canada have so far failed to produce results. Some have warned that U.S. trade law won't allow a November 30 vote on a U.S. -Mexico deal, because the Trump administration began the process seeking a trilateral one.
Trudeau said Section 232 tariffs on steel and aluminum, enacted on grounds of national security, are "a tool that the president has to use and he is using them because I think there's a sense that there are other tools that have to go through Congress that he doesn't get to use".
Canadian officials have said that despite the US threats to go it alone with Mexico, they do not believe Trump can by himself turn the 1994 pact into a bilateral deal.
Under a US legal process known as Trade Promotion Authority that was invoked to revamp NAFTA, Americans lawmakers need to review the text of the agreement 60 days before President Donald Trump can sign it.