What proportion of the members of a party have to be in favour of a "merger" for it to have validity in the eyes of the law?
At least two-thirds of the members of a party have to be in favour of a "merger" for it to have validity in the eyes of the law. "The merger of the original political party or a member of a House shall be deemed to have taken place if, and only if, not less than two-thirds of the members of the legislature party concerned have agreed to such merger," states the Tenth Schedule that is popularly referred to as the 'Anti-Defection Law'.