In 1821 the Russian czar had proclaimed that all the area north of the fifty-first parallel and extending one hundred miles into the Pacific would be off-limits to non-Russians. Adams had refused to accept this claim, and he told the Russian minister that the United States would defend the principle that the “American continents are no longer subjects of any new European colonial establishments.”Monroe’s principal concern had been to make sure that European mercantilism not be reimposed on an area of increasing importance economically and ideologically to the United States.