The prominence of U.S military forces in the region after the 1880s placed the emphasis on obtaining economic opportunity and strategic footholds from which the United States could move to obtain further opportunities. In the final decades of the nineteenth century, the British relationship with Canada made Great Britain one of the two major obstacles to U.S. expansionism. The opportunities for expansion seemed plentiful, but two problems, race and revolution, brought to a stop the plans of Grant to annex areas in the Caribbean region. Railroad builders had tried to lay track in the 1860s to link up with their own transcontinental system, but the plan fell to Mexico's anti-Americanism. The Good Neighbor approach in the 1889-90 conference produced an arbitration convention to help settle disputes, a recommendation to build a railroad uniting North and South America, and the establishment of the Commercial Bureau of American Republics.