I don't know if this deserves a new thread. But while everyone else was concerned with Pakistan, I've been looking into how Bharat can integrate its more friendly neigbours into a political union.
I understand that a few states have a want for an almost "nation-like" independence, including Tamil Nadu. I think the union should allow states to maintain their own "gendarmie" force. This would allow the joining nation to maintain their own armed forced for the defence of their culture/nation, while giving the union the powers of defence and foreign policy.
In Europe, these forces are essentially "armed police" that are deployed as: riot police, incidents involving weapons, special security services, international peacekeeping missions, generally as support for the police in harsh conditions, and as support for the military in calmer conditions.
I hope that the union can adopt a "multinational" rhetoric as found in other countries such as the UK or Russia, in addition to the federalism and EU-style political union (Nepal/Bhutan).