Ottawa should block Donald Trump’s chosen ambassador to Canada until the U.S. president stops questioning Canada’s sovereignty, says one expert.

“We could potentially use (this) as a way of signalling the seriousness with which the Government of Canada is viewing this unwelcome talk,” said University of Victoria international relations professor Will Greaves.

“It is an overt, aggressive policy that (Trump) seems to be shifting his administration to endorse. And if we are remotely serious as a country, we should regard that as a hostile action and embrace a wider array of tools in our response towards it.”