My Brother Is an Only Child(2007)

Original title: Mio fratello è figlio unico

Accio and Manrico are siblings from a working-class family in 1960s Italy: older Manrico is handsome, charismatic, and loved by all, while younger Accio is sulky, hot-headed, and treats life as a battleground — much to his parents' chagrin. After the former is drawn into left-wing politics, Accio joins the fascists out of spite, but his flimsy beliefs are put to test when he falls for Manrico's like-minded girlfriend.