What was the driving force of expansion in the american south?

1. foreign policy. Except for a brief interlude with Manifest Destiny in the 1840's, the country had been in a state of isolationism from the inception of independent government. Near the turn of the century, this policy changed to one of competitive interest in and foreign exchange with other countries. Industrial and mercantile expansion required new markets; the editorials and stories of the so-called "yellow press" sparked the interest of the people; religious missionaries spread their message to groups which expanded as rapidly as did modes of travel; as well as the acceptance (if somewhat altered) of the theory of Darwinism by the wealthy backers of government officials. Another cause of this policy shift was the mass colonization effort by the English, Germans, and Russia, and the American need for a superior navy. American factories and mills were producing far more than this country could consume, and foreign markets for export were desperately needed to sell off the excess.