An internal government report warned a year ago that allowing "the trend of negative rhetoric" about the security of the Canada-U.S. border could lead to a thickening of the 49th parallel, adversely affecting trade and travel.

The report, written by a diplomat at Canada's embassy in Washington, said that failing to refute U.S. claims about a "crisis at the northern border" would lead to the erosion of Canada's image as a secure neighbour.

The release of the February 2024 analysis through the Acce…