The phrase fifty-four forty or fight referred to?

Answer 1

It was the battle cry for people during the 1840s who wished to expand the US into Canadian territory. This was specifically used in the election of 1844 in which democratic candidate Polk tried to get expansionist votes.

The dispute originated from the claim that Oregon territory extended into Canada to the latitudinal line 54 40' degrees. However, in 1846, the Treaty of Oregon established that the US territory ended at the 49 degree line, the current boundary.