The government of Great Britain built railroads school and irrigation systems in colonial India primarily to "Strengthen its political and economic control in India."
Imagine that a country is fighting a war abroad: they need to have supplies sent to them. Those supplies need to be produced somewhere, and they're usually produced by the people back home, who also contribute to the war effort, but are not directly fighting. Those people are on the home front: at home but fighting.
For Canada, the home front would be in Canada.
The phrase "manifest destiny" is most often associated with the territorial expansion of the United States from 1812<span> to </span>1860<span>. This era, from the end of the War of </span>1812<span> to the beginning of the American Civil War, has been called the "age of manifest destiny".</span>