Dorothy Day and Thomas Merton shared a belief in the intrinsic good and equality of all human beings. These beliefs stemmed from their similar conceptions of God, which were informed by their Catholic faith. For example, Day and Merton modeled the virtue of equality on the Catholic premise that all people are created in God's image, holding that God's love precedes any human action and therefore also any judgment that can be levied on human action.
Aside from a few minor differences in their interpretations of scriptural content, the primary difference between the two progressive thinkers was the method each used to translate their inner beliefs into political change. Dorothy Day strove to utilize coalition politics to undermine predominant Catholic institutions that overlooked systemic issues of injustice. She focused on changing the Church's institutional identity, believing that challenging existing power structures was the best way to enact change.
Thomas Merton supported Day's actions, but thought of political change as something that occurs primarily at the site of the individual, who influences reality through thought, behavior, and devotion to Catholic moral tradition. He focused more on forming networks of individuals that transcended institutions and identities to engage in peaceful protest.