2. The Atlantic article: "Walt Whitman's Guide to a Thriving Democracy" (May, 2019) by Mark Edmundson 
https://www.theatlantic.com/magazine/archive/2019/05/walt-whitman-leaves-of-grass-american-democracy/586045/ 

"America had a mind shaped by its Founders, but the country needed the poet to discover its spirit."

3. Commentary on the 1855 edition, from the Walt Whitman Archive: 

https://whitmanarchive.org/criticism/current/encyclopedia/entry_21.html 

“The importance of the first edition of Leaves of Grass to American literary history is impossible to exaggerate. The slender volume introduced the poet who, celebrating the nation by celebrating himself, has since remained at the heart of America's cultural memory because in the world of his imagination Americans have learned to recognize and possibly understand their own. As Leaves of Grass grew through its five subsequent editions into a hefty book of 389 poems (with the addition of the two annexes), it gained much in variety and complexity, but Whitman's distinctive voice was never stronger, his vision never clearer, and his design never more improvisational than in the twelve poems of the first edition.”