Former Union home and finance minister P. Chidambaram is busy putting together the Congress manifesto before the forthcoming general elections. His book Undaunted: Saving the Idea of India (Rupa), a collection of his articles published in The Indian Express in 2018 is just out. Chidambaram talks to Satish Padmanabhan on a range of topics from the Pulwama terror attack, the grand opposition alliance to Rafale deal and cow vigilantes. Excerpts…