Why is "American literary nationalism" trending?

Wikipedia Overview

American literary nationalism was a literary movement in the United States in the early-to mid 19th century, which consisted of American authors working towards the development of a distinct American literature. Literary figures such as Henry Wadsworth Longfellow, William Cullen Bryant and William Ellery Channing advocated the creation of a definitively American form of literature with emphasis "on spiritual values and social usefulness." Longfellow wrote that "when we say that the literature of a country is national, we mean that it bears upon it the stamp of national character." Many authors of the time also advocated tying the literature to religion. These demands were also couched in a perceived contrast between the English author as a "well-off amateur writer ... who writes in his spare time for personal amusement" and the American as a "professional author, writing out of economic necessity".