If the BJP wins in 2019, will India become Hindu Pakistan?

This is just nonsense. India is perhaps the only country in the world where minorities have not only equal rights, but also more rights (certain additional rights) than the majority community. Read the Constitution and the additional rights given to the minority communities under Part III relating to fundamental rights. The rights that have been given to the minority institutions, have not been given even to the institutions of the majority community. Further, there are political parties that indulge in minority appeasement.

BJP is in power since 2014. Yet, we have the same Constitution that was enacted in 1950. How does it make a difference if the BJP wins the power again in 2019?

This is just a figment of imagination of Shashi Tharoor, who has made this silly statement (of India becoming a Hindu Pakistan if BJP wins in 2019). He just wants to scare the minority communities for gathering votes for Congress. He has a habit of making statements to remain in media glare; if nothing else, he will try to search some little-used word from English dictionaries and throw it in some tweet. Perhaps, this time, he did not find any new English word, hence this jumla. After a charge sheet has been filed against him for the offence of abetment of suicide of his wife (Sunanda Pushkar), he has suddenly become more active in politics. Seeking political relevance.

India is India, Bharat and Hindustan. By whatever name you call it. But, it can (and will) never become Pakistan-like.