Compared to almost all of the other characters, Levin is portrayed as the most Russian because of his beard, his love of farming and his preference for the country. On page 350, he even becomes "disgusted with himself" for using non-Russian words.
Throughout the novel, we see Levin coming into contact with more Western ideas (like communism) and characters (like Oblonsky). As he tries to process these influences and situate them within his own personal philosophy, Levin fluctuates between experiencing overwhelming self-doubt and intense pride. Similarly, as new methods of transportation began to connect Russia to the west, the country became more self-conscious of its backwardness and equally aware of the uniqueness of its spread-out, agricultural society. I think the dichotomy between Russian self-doubt and self-confidence is particularly evident in the scenes at the European spa. While Kitty and her mother try to act more European and even feel shame for Nikolai when he acts as a sloppy representation of Russia, the Prince exaggerates his Russian qualities and rejects European behavior.
If we accept Levin as a symbol of Russia for his wildness and the moments he alternates between self-doubt and confidence, we are using the same justification that connects him to Tolstoy. This has interesting implications for Tolstoy's presentation of himself, since he's clearly proud of his Russian-ness. This could explain why he seems more sympathetic to the more Russian characters, like Levin and the Prince.