Bihar Chief Minister Nitish Kumar will exit the state's ruling Mahagathbandhanand, by extension the now-stuttering Congress-led INDIA opposition bloc, and re-ally with Prime Minister Narendra Modi's Bharatiya Janata Party ahead of the April/May Lok Sabha election, sources told NDTV Thursday.

News of a fifth U-turn by the Janata Dal (United) boss - who has jumped between the BJP, Congress, and/or Lalu Yadav's Rashtriya Janata Dal since 2013 - has triggered speculation over what led to the latest jump. At (or near) the top of the list of probable causes is the BJP's decision to award former Bihar Chief Minister Karpoori Thakur a posthumous Bharat Ratna - India's highest civilian award.

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Mr Thakur was an iconic socialist leader who was Chief Minister twice in the 1970s, and is credited with implementing the state's contentious alcohol prohibition policy. Still remembered today as 'jan nayak', or 'leader of the people', Karpoori Thakur's legacy remains a valuable asset for political parties today.

He was also Nitish Kumar (and Lalu Yadav's) mentor, and both had strongly advocated the award.

READ | Ex-Bihar Chief Minister Karpoori Thakur Gets Posthumous Bharat Ratna

After the award was confirmed - Mr Modi did so on X and hailed Mr Thakur as "a champion for the marginalised and a stalwart of equality and empowerment" - Nitish Kumar thanked the Prime Minister.

He also took a potshot at the Congress; he said he had petitioned every central government since 2007 (when the Congress was in power) and it was only the Modi government that responded.

However, he also took a dig at Mr Modi, declaring he expected him to "claim full credit". "I was told by Ram Nath Thakur (Karpoori Thakur's son... the PM called him up... PM has not called me so far..."

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The BJP's decision to honour Karpoori Thakur has been seen as a strategic move.

For one thing, over 60 per cent of Bihar's 13.1 crore population belong to backward or extremely backward communities, among whom Mr Thakur is still revered. Awarding his estate a Bharat Ratna will only help the BJP gain traction with this massive vote bank in a state that has 40 Lok Sabha seats.

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In addition, a Bharat Ratna for the former Chief Minister may have put additional pressure on Nitish Kumar to make a choice - stay with the INDIA bloc (within which the JDU leader was already unsettled, claiming disrespect after being passed over as a possible Prime Minister candidate) or do a ghar wapsi.

For the BJP, having Nitish will mean a wider appeal in the Lok Sabha election. In 2019 the JDU won 16 seats, the BJP 17 and the Lok Janshakti Party six, meaning the "Modi wave" swept the state.

The BJP will want a similarly emphatic win this year to hit its target of 400 Lok Sabha seats.

A tie-up with Nitish Kumar does have its pitfalls, though, chief among which is his tendency to go back-and-forth between allies. His prime ministerial ambition is also an open secret.

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That will absolutely not be fulfilled at this time, with Mr Modi all but certain to win a third term, but there may be other incentives on offer for the Bihar leader, including a second stint at being a Union Minister.

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