What does the BJP’s victory in West Bengal mean for India’s democracy?

India's West Bengal state has been governed by opposition parties for nearly 50 years, first by the communists and then by the centrist Trinamool Congress for 15 years. However, the Hindu nationalist Bharatiya Janata Party (BJP) has now swept to victory in the state assembly polls, marking its first win in the state. Critics claim a controversial revision of the electoral roll helped secure the BJP's landslide win.