! "and that claim is by the right of our manifest destiny to overspread and to possess the whole of the continent which providence has given us for the development of the great experiment of liberty and federated self-government entrusted to us." --john l. o'sullivan, new york morning news, 1845. o'sullivan argued that american expansion and imperialism was justified because a) gaining new territory would allow democracy to spread throughout the continent. b) america needed to seize territory to prevent future conflicts with foreign powers. c) it would lessen the tensions between white settlers and the native americans. d) the vast number of new immigrants entering the country necessitated such expansion.