One core theme in Rankine's Citizen: An American Lyric is the nefarious subtlety of "new racism" in a world that often alleges itself triumphantly to be "post-racial." Rankine tries to typify the different instances of racism she and her friends still experience, paying particular attention to microaggressions. Qualifying her intellectual analysis, she is wary of the advent of academic neologisms which often distract from, trivialize, and obfuscate racist behaviors.

Another theme is the cumulative nature of racism. Rankine thinks of racism, and other normative but deficient social orientations, as a kind of organism that evolves and pervades over time. Racist individuals renew their own racism by repeating and inventing racist behavior; it does not matter whether these behaviors are blatant or vanishingly small. Rankine contends that the disease of racism infects the imagination, distorting reality. She believes that the distortion of white people's imagination about black people leads directly to such atrocities as the rampant police executions of innocent black people.