While the BJP has the numbers to send its eight candidates to the Upper House, its ally, Suheldev Bhartiya Samaj Party (SBSP), which has four MLAs in the 403-member UP Assembly, holds key to the fate its ninth nominee.
The Samajwadi Party and the Bahujan Samaj Party exude confident they would win two of the 10 seats. The polls are scheduled for March 23.
"...How can I tell you that whether we will be voting for the BJP or any other party in the Rajya Sabha elections? We are yet to take a final stand on this," SBSP chief Omprakash Rajbhar told PTI.
Mr Rajbhar said his party was not consulted by the BJP before announcing the candidate.
"We are still in alliance with the BJP," he said, "but did they ever consult us before finalising their candidates for the Rajya Sabha elections and Lok Sabha bypolls (to Gorakhpur and Phulpur)?"
"They fielded their candidates in the urban local bodies polls, but did they appropriately discharge the alliance dharma...In the Lok Sabha bypoll did they ever ask the alliance partners what could be their possible roles?" he rued.
The SBSP chief also said, "Unless someone (from the BJP) asks us, how will talks take place? Should I on my own go and say that I will vote for you."
"...Finalising the candidate is their job, not ours. But, as a courtesy they should ask at least once as to whether we will join them in campaigning. Not a single leader asked us. In this scenario, how can I tell you whether we will be voting for the BJP or any other party in the Rajya Sabha elections. We are yet to take a final call."
On whether his party will cross-vote, Mr Rajbhar, who is also a cabinet minister in the Yogi government said, "We are in alliance, and if they do not discharge the alliance dharma, should we go to them and say that please take our vote?"
He claimed his party could have influenced at least 30,000 votes in the Gorakhpur Lok Sabha bypolls and the results could have been otherwise. "But, it seems we have no utility (for the BJP). Similarly, in Phulpur, we were not invited even once to campaign for the BJP candidate," he said.
A sulking Rajbhar also said, "You have kept us in alliance...either I don't know how to discharge the alliance dharma or I am saying something wrong...The nominations for the Rajya Sabha elections have been done. But, is it not the duty of the BJP to consult us and deliberate on the election."
The president of the SBSP observed that the dalits and backwards classes have been "ignored", and this trend is continuing.
However, seeking to downplay SBSP's annoyance, state BJP spokesperson Manish Shuka said, "All our alliance partners are with the BJP. Both the Apna Dal (Sonelal) and SBSP are with the BJP. I am confident that they will vote for the BJP in the Rajya Sabha elections.. The alliance is in best of health and all the partners are together."
Mr Shukla also exuded confidence that all the BJP candidates will win the Rajya Sabha elections.
The BJP and its allies currently have 324 seats in the Assembly after the death of its Noorpur MLA in a road accident recently and to secure a straight win in this Rajya Sabha election, a candidate needs 37 first preference votes.
Thus, arithmetically, the BJP can easily win eight of the 10 seats and be left with 28 surplus votes.
If the SBSP decides not to go with the BJP, even then the eight candidates of the BJP will smoothly sail through, and the party will be left with 24 surplus first preference votes.
"There can be some contest on the ninth seat," a senior UP BJP leader said.
With 19 MLAs, the BSP is short of 18 first preference votes, and with Naresh Agarwal's son Nitin, who is still an SP MLA, likely to cross-vote for the BJP, the task will become difficult for Mayawati's candidate Bhimrao Ambedkar.
After the new found bonhomie with the SP, Mayawati is banking on the 10 surplus votes of Akhilesh Yadav's party, besides seven votes of the Congress and one of RLD to reach the magic figure of 37 votes.
However, Nitin Agarwal can queer the BSP's pitch if he votes for the BJP.
Naresh Agarwal, who recently quit the SP and joined the BJP, has said his son would vote for the saffron party in the Rajya Sabha polls.
The country's most populous state sends 31 MPs to the 245-member Rajya Sabha, and the BJP, which won a massive victory in the 2017 Assembly elections, is yet to get a lion's share of these.
With 83 members in the Upper House, the NDA is well short of a majority. The BJP has 58 Rajya Sabha MPs.
The BJP candidates in the fray from UP are Union Finance Minister Arun Jaitley, Ashok Bajpai, Vijay Pal Singh Tomar, Sakal Deep Rajbhar, Kanta Kardam, Anil Jain, Harnath Singh Yadav, GVL Narasimha Rao and Anil Kumar Agarwal.
The SP has fielded Jaya Bachchan and BSP Bhimrao Ambedkar.