I think that there are some distinct traces of Romanticism in James's novella. One such remnant would be the work's depiction of social conventions. Romanticism was a movement predicated on the individual remaining apart from the larger social conventions that enveloped them. In placing such a strong importance on the subjective, the Romantic thinkers sought to embrace non- conformity and placed importance on individuals remaining separate or distinct from the social realm. The outsider classification is highly Romantic, in scope. The Romantic thinkers believed in the outsider as having more insight than one deemed an "insider." For example, Wordsworth is an outsider in poems like "The Solitary Reaper" and Coleridge praises the outsider as the force of narration in "The Rime of the Ancient Mariner." The "outsider" possesses a Romantic understanding that those who are socially accepted and conform to external notions simply lack.
James echoes this in Daisy Miller. Daisy herself is an "outsider." She is unaware of the social conventions that seek to define her in Europe. She is literally an "outsider" as she is from America. She is literally positioned on the outside and is perceived by "the insiders" as such. In their initial interaction, Daisy's eyes are described as "singularly honest and fresh" as well as "wonderfully pretty." In this description is not only a praising of an outsider, one whose beauty exists outside of socially conformed notions of the good, but also a lauding of the authentic expression of the "honesty" in her eyes, a definite element in Romantic construction of beauty. James embraces and seizes upon this Romanticism in describing the initial attraction between both Winterbourne and Daisy:
In Geneva, as he had been perfectly aware, a young man was not at liberty to speak to a young unmarried lady except under certain rarely occurring conditions; but here at Vevey, what conditions could be better than these?—a pretty American girl coming and standing in front of you in a garden.
The purity of attraction, reflective of the garden and natural conditions, are elements that lie outside of social conformity. These are Romantic articulations of the good. Within this instant is a freedom and sense of unique expression that are fundamentally Romantic because of their true and real discovery. In this light, traces of Romanticism can be seen in James's description of Daisy.
Another trace of Romanticism can be seen in the perceived sense of tragic collision that Daisy suffers. Romantic thinkers were attracted to the idea of the forlorn and marginalized voices that lived as the outsiders. For example, the "Byronic hero" is often on the periphery of society and rarely experiences social acceptance. When Shelley writes about the essence of poetry, he does so with an understanding that the poet is not going to experience full acceptance and validation within their existing social order. This tragic predicament is seen in Daisy Miller. When Winterbourne sees in her this tragic realization, it is poignant and highly Romantic in tendency:
Daisy turned very pale and looked at her mother, but Mrs. Miller was humbly unconscious of any violation of the usual social forms. She appeared, indeed, to have felt an incongruous impulse to draw attention to her own striking observance of them. "Good night, Mrs. Walker," she said; "we've had a beautiful evening. You see, if I let Daisy come to parties without me, I don't want her to go away without me." Daisy turned away, looking with a pale, grave face at the circle near the door; Winterbourne saw that, for the first moment, she was too much shocked and puzzled even for indignation.
The fact that Daisy experiences social ostracizing and then must die from a fever that she has little defense against is a reflection of the Romanticism in the work. She dies from her flouting of social conventions. This is Romantic because it is almost as if Daisy's sense of purity and sense of unconformity was "too good" for the world around her. She dies young and dies an unnatural death, which are elements of Romanticism. Her death is a reflection of how social conformity still stands, taking the outsider voices of dissent as collateral damage. This would be attractive to the Romantic thinker, and represents how traces of Romanticism can be found in James's work.