Millay was particularly well positioned to have an impact on the politics of twentieth-century poetry because she was seen by many as a prototype of the "modern woman," especially in her assertion of the right to and need for female self-determination of body, mind, pocketbook, and voice. Virtually from the beginning of her career, critical discussion of Millay, favorable and unfavorable alike, had tended to treat her not merely as an individual writer but as an exemplary instance of "the woman as poet," as John Crowe Ransom put it. Thus her turn in the late 1920s toward poetry as an expression and potentially a form of political commitment was not merely an individual choice, but implied the potential for a broader scope for female poets at large.

The immediate external catalyst of Millay’s politicization, of course, was the Sacco-Vanzetti case.… The first expression of her nascent agenda of progressive dissent emerged strikingly on August 22, 1927, the day before the execution, with the publication of her poem "Justice Denied in Massachusetts" in the New York Times.… In this context, surrounded by worldwide protests and the preparations for the executions, "Justice Denied" functioned quite literally as news, as its title, modelled on a screaming newspaper headline, acknowledged. Indeed, the poem scornfully exploited the contrast between its title and its traditional conceptual structure of the allegorical landscape. The latter demanded that readers recognize that this was not just political sloganeering but was in fact a poem by a famous and revered poet, while the former refused to abstract or universalize the political dimension of existence to a comfortable distance, as poems so often tend to do. Millay’s allegory mounted a critique of the forces of "quack and weed" which had choked the land’s rich inheritance of social justice, leaving "a blighted earth to till / with a broken hoe." The detail of her allegorical arrangement implicitly presented Millay’s vision of an ideal democracy and the current despoilation of American political freedoms: the land itself was sweet, bountiful and meant to be shared in common; the evil came from choking weeds, cancerous growths which interrupted the beneficent domestic processes of growing corn and larkspur....

The setting which framed the poem’s description of the blighted land, "the sitting room" – traditional haven of the bourgeoisie – offered no comfort to the collective speaker, ironically becoming part of the poet’s stinging rebuke to those who had never committed themselves to the protest wholeheartedly, or who had given up too easily. Millay used persistent echoes of Eliot’s "The Love Song of J. Alfred Prufrock" ("Let us abandon our gardens and go home / And sit in the sitting-room"; "Let us sit here, sit still, / Here in the sitting-room until we die"; "We shall not feel it again. / We shall die in darkness, and be buried in the rain") to mock the fashionably alienated stance toward contemporary society exemplified by Eliotic high modernism. The phrase which served as the refrain in these passages functioned not only as a conventional grammatical marker of future intention (as in "Let us go then, you and I"), but also as a plea from the enervated collective narrator for release from the exhausting burden of social responsibility ("let us go"). As her scornful portrayal of this persona suggested, the poet would not let her audience go with a clear conscience from the struggle for these gardens of America.

Those commentators unsympathetic to Millay’s efforts to write poetry of explicit political critique have treated "Justice Denied in Massachusetts" as somewhat of a notorious fall from grace, the poet’s first betrayal of her "natural lyrical gift." In 1935, for example, Cleanth Brooks [in "Miss Millay’s Maturity," a review of Wine from These Grapes in Southwest Review 20] used the poem as a lynchpin of this argument that Millay’s "preoccupation with social justice" had yielded "disappointing" results. In order to do so, however, Brooks had to contort the poem into offering the "advice" that "those who loved justice" should "‘sit in the sitting room,’ convinced that justice was truly dead and that no other effort in behalf of justice was worth making" (1), exhibiting a lack of sensitivity to the poet’s irony which was downright astonishing in a critic who would later make irony a constitutive element of his theory of literature. Recognizing no difference between the poem’s speaker and the poet, Brooks went on to patronize Millay as having the "attitude … of a child whose latest and favorite project has been smashed" (1-2), evoking the equation of woman – even woman writer – with child.