As things stand, incumbent Vice President Ansari has the pledged support of at least 453 votes in an electoral college of 790 MPs, much above the required number of 396.
Singh, former Finance and External Affairs Minister, has the committed support of 218 votes in the electoral college which comprises 545 members of Lok Sabha and 245 members of Rajya Sabha.
Except for Trinamool Congress with 28 MPs, all the constituents of UPA are solidly behind Ansari, whose candidature was declared last Saturday after a meeting of the allies. Trinamool is yet to make up its mind.
Ansari also has the support of UPA's outside supporters Samajwadi Party and BSP besides CPI(M) and Forward Bloc.
There are 119 MPs of different parties who are yet to announce their preference.
Even if all these MPs pledge support to the NDA nominee, Singh can muster only around 340 votes.
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The parties which have pledged support for Ansari are: Congress (278), BSP (36), SP (31), CPM (27), DMK (25), NCP (16), RLD (5), RJD (5), National Conference (5) and others which include Forward Bloc, Muslim League, AIMIM, AIUDF, Kerala Congress (Mani), VKC, BVA, NPF, SDF and Swabhiman Paksha.
For Singh, BJP has 163 MPs, JD-U 29, Shiv Sena 15, Akali Dal 7 and others like JMM three and Haryana Janhit Party one.
BJD with 21 MPs and AIADMK with 14 MPs, which are with NDA in supporting P A Sangma in the Presidential poll, have not revealed their stand so far.
RSP with two MPs has decided to abstain from voting.