New Delhi: It’s a crucial day for PA Sangma. The man who quit the Nationalist Congress Party (NCP), which co-founded several years ago with Sharad Pawar so that he can run for the post of President of India, will today know whether he will get the support of the BJP in his bid.

But even if the BJP decides on Mr Sangma, the big hurdle will be getting all its allies in the National Democratic Alliance to back him.

BJP leader Sushma Swaraj will address a press conference today but there is no word on whether an announcement on the presidential poll will be made.

The last date for candidates to file their nomination papers is June 30.

Refusing to give up his run for the post of President without a fight, Mr Sangma resigned from his party yesterday after the NCP insisted that he stand down so that Pranab Mukherjee, the UPA’s choice, could win. The NCP is a member of the ruling coalition, the UPA.

The conundrum for the BJP is that its allies, the Shiv Sena and Nitish Kumar, have confirmed they will support Pranab Mukherjee, who is the candidate of the Congress-led UPA. So the BJP has to decide whether to join Tamil Nadu Chief Minister J Jayalalithaa and Odisha Chief Minister Navin Patnaik, who have declared Mr Sangma as their candidate.

Mr Sangma’s party was hopeful of persuading him to withdraw from the contest. But a visit from Janata Party president Subramanian Swamy in the evening indicated that the BJP was persuading Mr Sangma to make his candidature official.

Mr Sangma has a few dilemmas of his own to consider. He was a co-founder of the party he quit. His daughter, Agatha, is a junior minister in the UPA government. Given that he has quit the NCP, she may be asked to surrender her portfolio. The Congress says that is a decision that has to be taken by her party president, Mr Pawar.

The math is also problematic for Mr Sangma. Mr Patnaik and Jayalalithaa, his official sponsors, hold 6% of the vote. If the BJP jumps on board, Mr Sanmga manages 26% of the vote. An additional 4% comes his way if he wins the endorsement of Mamata Banerjee, who is a member of the UPA but has refused to support Mr Mukherjee. That adds up to just 33% of the electoral college.

The BJP knows it’s unlikely to defeat Mr Mukherjee. But its leaders feel that unless they put up a fight against the UPA for President, votes will dismiss them as an opposition only in name ahead of the general elections in 2014. Teaming up with Jayalalithaa and Mr Patnaik also offers the party an opportunity to woo them into its coalition.

Mr Sangma’s odds will be heavily influenced by the Left, which meets today to decide who to back in the Presidential election. The four Left parties have 4.7 per cent of the vote. Sources say Left parties are unwilling to support a candidate propped up by the BJP.