Style: Some poetic styles are more prevalent in American literature than others. For example, free verse is a common form of poetry in American literature, while sonnets are more common in European literature.
Author's nationality: Poems written by American authors are considered American literature, regardless of their subject matter or style.
Here are some specific examples of poems that are considered American literature:
* "The Star-Spangled Banner" by Francis Scott Key
* "I Hear America Singing" by Walt Whitman
* "Stopping by Woods on a Snowy Evening" by Robert Frost
* "The Waste Land" by T.S. Eliot
* "Howl" by Allen Ginsberg
* "The Colossus" by Sylvia Plath
* "Citizen: An American Lyric" by Claudia Rankine
These poems all have different subject matter, styles, and authors, but they are all considered American literature because they deal with American themes or settings, are written by American authors, or are written in a style that is common in American literature.