One of two municipios that Isabela Mayor Carlos Delgado Altieri lost in the 2020 PPD Primaries, San Juan, resulted in an interesting coalition that is incredibly revealing as to the city's political landscape.
Carlos himself came within 4% of winning the city because of his strength in the Prediminantly PNP areas, such as the Caseríos in Sabana Llana Norte and Gobernador Piñero and Eastern Santurce (Subbarios Obrero, Las Casas, Merhoff, Shanghai, & Villa Palmeras)
By Contrast, Former Senate President and then Senate Minority Leader Eduardo Bhatia was strongest in the Educated Barios of Monacillo, Monacillo Urbano, Hato Rey Sur, El Cinco, the northwest of Santurce and Viejo san Juan, despite losing the northwest tip to then SJ Mayor Carmen Yulín Cruz Soto.
Carmen Yulín herself Did well in the University Bario, Hato Rey Central and Oriente, due to a mixture of her strength with the Colege students thtere and the support she got by the Christian Mita Congregation.
Combined, Bhatia and Yulín also did incredibly well in Sabana Llana sur, coming in at a combined ~60% despite Charlie winning the area outright.
bhatia's and Yulín's performance in the city is due to a mixture of educated and upscale puerto Ricans, most of which went for Bhatia, and some for Yulín, in addition to Yulín doing well in the university of Puerto Rico and the Soberanista Christian Mita Congregation that functionally block voted for her.
In the end, as mentioned earlier, despite losing the city by 4% thanks to his showings in the Caseríos, Due to landsliding the rest of the Island, Carlos "Charlie" Delgado Altieri was nominated as the PPD's Gov candidate, and went on to lose the General election to now Governor, Pedro Pierluisi (PNP)