WASHINGTON -- Stephen Harper says he believes Donald Trump is genuinely willing to pull the plug on the North American Free Trade Agreement.

The former prime minister is in Washington to discuss the fate of the ongoing trade negotiations, making rare public comments on a current political issue.

And he happened to be doing so at the very moment his successor Justin Trudeau was a few blocks away at the White House, discussing the same issue with the U.S. president.

The former Conservative leader, who's known as an ardent free trader, says powerful anti-trade forces that predate Trump's presidency are at play in American society and aren't going away anytime soon.

Harper says he understands the frustration: he described his annoyance at spending his 50th birthday signing a bailout package for General Motors Canada, only to see the auto giant move jobs out of the country.

He says he is advising companies to start planning for the possibility of a world without NAFTA.

On the other hand, Newt Gingrich -- a Trump ally who was speaking on the same panel -- is sounding a more optimistic note.

The former House speaker and friend of the president says a deal will eventually be reached, after long and difficult negotiations.