 Nehru served as the prime minister for eighteen years.During his tenure he had many ministers in his cabinet who were heavy weights in their own right.Key members from his first cabinet include Vallabhbhai Patel who oversaw the integration of princely states in the Indian union but was also his greatest rival in the Congress party, and B. R. Ambedkar, the law minister in the interim cabinet who also chaired the Constitution Drafting Committee.