Most of the books published during the five-year period leading up to, during, and after the invasion of Mexico were war-mongering tracts. Euro-American settlers were nearly all literate, and this was the period of the foundational "American literature," with writers James Fenimore Cooper, Walt Whitman, Edgar Allan Poe, John Greenleaf Whittier, Henry Wadsworth Longfellow, James Russell Lowell, Ralph Waldo Emerson, Henry David Thoreau, Nathaniel Hawthorne, and Herman Melville all active-each of whom remains read, revered, and studied in the twenty-first century, as national and nationalist writers, not as colonialists...Emerson supported territorial expansion at any cost but would have preferred it take place without war.