It鈥檚 been a month since the White House gave the official 90-day warning to Canada and Mexico that it plans to renegotiate NAFTA, a trade deal that U.S. President Donald Trump has vowed to rewrite or scrap altogether.

But David Frum, senior editor of The Atlantic, has doubts that the Trump administration will be able to close the deal.

鈥淭he Trump administration has no capacity to get things like that done. As you鈥檝e seen, they鈥檝e been unable to pass major legislation. Writing a treaty like this involving three countries is a major undertaking,鈥 he told CTV鈥檚 Power Play on Thursday.

Frum pointed out that several key positions necessary to get the ball rolling have yet to be filled, including an intellectual property negotiator and several senior trade roles.

鈥淪o how do they even begin this process? And if the president were to cancel NAFTA without something in its place, that would fall heavily on a lot of pro-Trump states -- Iowa and Arkansas -- and other major agricultural exporters,鈥 Frum said.

鈥淚 find it hard to imagine that this talk is going to turn into anything more than talk.鈥

Frum, a conservative political commentator and former speechwriter for George W. Bush, has been an ardent critic of Trump. Speaking to CTV鈥檚 Power Play, Frum responded to Trump鈥檚 latest Twitter outburst. On Thursday, Trump tweeted that is unfolding amid reports that he is being investigated by special counsel Robert Mueller for potentially obstructing justice.

The Washington Post has reported that the widening scope of the investigation was prompted by the firing of former FBI director James Comey, who has testified under oath that Trump demanded a vow of loyalty from him.

But there鈥檚 a basic fault in Trump鈥檚 鈥渨itch hunt鈥 accusation, Frum said.

鈥淭he point of witch hunts is we鈥檙e supposed to believe there are no witches,鈥 Frum told CTV鈥檚 Power Play on Thursday. 鈥淏ut that Russia attacked the American democratic process -- that鈥檚 just a fact. And that Donald Trump accepted that help and benefited from it and publically welcomed it, that鈥檚 also a fact.鈥

What is uncertain is whether Trump in any way co-ordinated with this effort. And that is a question that we鈥檒l get to the bottom of.鈥

Frum suggested that Trump will face even more questions if -- as some reports have suggested -- he chooses to fire Mueller.

鈥淚f the president first fires the director of the FBI and then the special counsel, people begin to think: 鈥楬e looks really guilty, doesn鈥檛 he?鈥欌

Trump has nominated Kelly Knight Craft, a top Republican donor, as U.S. ambassador to Canada. Frum called Knight Craft a standard-issue Republican who is 鈥渘ot a friend of Trump鈥 and suggested her appointment could be mired by delays.

鈥淭rump has a habit, and he did this for example with the ambassador of the U.K., of announcing the nomination and then never getting it together even to submit the paperwork to the Senate, much less for the nomination to be acted upon within the Senate,鈥 he said.

Even so, Knight Craft鈥檚 appointment isn鈥檛 expected to cause a major stir, Frum said.

鈥淏asically it鈥檚 a pretty hard job to mess up, ambassador to Canada, it鈥檚 a very strong relationship and very little of it goes through the ambassador鈥檚 hands.鈥