He earned reputation as a giant killer when he defeated the RJD's Raghuvansh Prasad Singh in the 2014 Lok Sabha elections.
As union minister Ram Vilas Paswan tackles tricky negotiations over seats with the BJP and other allies in Delhi, there is worrying word from back home in Bihar where an important leader of his Lok Janshakti Party or LJP has quit all party posts.
Rama Singh, the LJP lawmaker from Vaishali, says he is upset because the party has not involved him in the key process of discussing division of seats for the Bihar elections with the BJP.
Mr Singh had earned the reputation of a giant killer last year when he defeated Raghuvansh Prasad Singh, a very popular leader from Lalu Yadav's RJD, in the national election. LJP leader and Mr Paswan's son Chirag had then praised Rama Singh as "a true politician."
Sources said among the many grouses that Rama Singh has against his party is Bollywood-actor-turned-politician Chirag Paswan's elevation as de facto chief of the LJP. Chirag Paswan, has reportedly rejected the lawmaker's request for a ticket for his wife to contest the Bihar elections.
Rama Singh, said sources, has also privately grumbled about his diminished importance in party affairs since Mr Paswan junior, 32, took charge, despite his having loyally stood by Ram Vilas Paswan through some rough years. In the last Assembly elections in 2010, the LJP could win not a single seat in Bihar.
But in the national election last year, the Paswan party came back strongly, winning six of the seven Lok Sabha seats it contested as a BJP ally, among them Rama Singh's spectacularly won seat.
The lawmaker is now said to be contemplating walking over to the rival camp led by Chief Minister Nitish Kumar for a ticket for his wife.
Rama Singh is a Rajput leader with an upper caste base and has the potential to transfer some votes to the other side. More importantly, in a closely contested election, the BJP alliance can ill-afford being seen as losing prominent leaders to the other side.