How Tamil Nadu's regional nationalism, habitual secularism of a plural society in Kerala halted BJP's march on the South

Historically, the insurmountability that the BJP faces in south India arises mainly from Tamil Nadu and Kerala, but their stories of resistance - the politics, the underlying ideologies, and the circumstances - are completely different from each other. One is strongly based on self-respect and counter-nationalism while the other is based on the habitual secularism of a plural society and age-old Centre-Left politics.