Maya Jasanoff in the New York Review of Books, reviewing Walter Johnson's River of Dark Dreams: Slavery and Empire in the Cotton Kingdom:
. . . it takes some effort to recall the flexibility of borders in generations past. At the time of the Louisiana Purchase , what we think of as the deep South was really the Far West. At time of the Monroe doctrine , Texas was part of Mexico, and Oregon jointly administered by Britain. At the time of the Gold Rush , the fastest way to get to California involved going south to Central America, crossing the isthmus, and sailing up the Pacific coast. What all this meant was that, if you looked at the world from New Orleans or Natchez, you didn't necessarily see the future of your country in the West.
Nathaniel Philbrick on teenagers 200 years ago:
Today it is difficult to appreciate the level of patriotism commonly felt by those of Wilkes's generation [born 1798], many of whose fathers were fighting in the War of 1812 and whose grandfathers had fought in the Revolution.
Nathaniel Philbrick, Sea of Glory: America's Voyage of Discovery, The U.S. Exploring Expedition, 1838-1842 (New York: Penguin, 2004), 7.
Maya Jasonoff, "Our Steamboat Imperialism," New York Review of Books vol. 60 no. 15 (10 October 2013), 47.
Harold Henderson, "For the historical context file," Midwestern Microhistory: A Genealogy Blog, posted 27 September 2013 (http://midwesternmicrohistory.blogspot.com : viewed [date]). [Please feel free to link to the specific post if you prefer.]