Northern boundary of Oregon territory jointly occupied with Britain advocated by democratic party?

The northern boundary of Oregon territory was parallel 54° north. At the time, a treaty called for the joint occupation of this territory by both American and British settlers. More and more Americans began to settle there, however, during the 1840s in a bout of "Oregon fever." James K. Polke, the largely unknown presidential candidate and democrat, recognized the potential of reigning in this movement for his purposes. He thus advocated expansion that would encompass California, Texas, and all of Oregon territory, running on a slogan of "fifty-four forty or fight!"