In the two last Presidential elections, the Sena had not backed the NDA choice. In 2012, it had voted for UPA candidate Pranab Mukherjee and in 2007, it had backed UPA candidate Pratibha Patil. Though it has been the BJP's oldest ally, the Sena has been vocally critical about a number of decisions of the government at the state and the Cetre.
With its 18 parliamentarians and 63 legislators, the Sena has control over 25,893 votes of the presidential collegium. If it chooses to support the BJP, it could help the NDA candidate to get elected comfortably.
The NDA has already reached out to the opposition seeking meetings with Congress chief Sonia Gandhi and the Left later this week. BJP chief Amit Shah has formed a committee for conducting the negotiations, which include the government's seniormost ministers -- Rajnath Singh, Arun Jaitley and Venkaiah Naidu.
The Sena has been pitching Mohan Bhagawat, the chief of BJP's ideological mentor Rashtriya Swayamsevak Sangh for the nation's top post. And with the BJP showing little interest in the idea, the Sena had indicated last week that it may not support the NDA candidate during voting in the Presidential election.
"We may take an independent stand over casting our vote in the upcoming Presidential election," Sena spokesperson Sanjay Raut was quoted as saying by news agency Press Trust of India. Mr Bhagwat, he had added, was "more capable" than anyone else "fulfilling the dream of Hindu Rashtra (Hindu nation)".
Mr Bhagwat has denied that he is in the reckoning. But even so, Mr Raut raised speculation again yesterday by asking why Mr Bhagwat was "not a suitable candidate for the post of president?". For the Sena, Mr Bhagwat remains "first choice," he had added.
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