Insurmountable Invading Difficulty

Travels through Canada, and the United States of North America: in the years 1806, 1807, and 1808:

Besides its [Quebec's] local advantages, it is separated by immense forests and rivers from an invading army of the United States, the only country from which Quebec has any thing to dread while it remains in the hands of the English.

Should a war ever take place between Great Britain and the United States, it is more than probable that the latter would attempt to conquer Canada. Their great object would be to drive us from the American continent, as much as to obtain an equivalent in the event of peace. 

The difficulty of bringing with it a large battering train would, I think, prove insurmountable; and without that all their attempts to get possession of the city must fail, provided the works were well-manned. As long as we retain the capital in our hands the country can never be conquered.