Nitish Kumar on Thursday filed his Rajya Sabha nomination, dramatically heralding the end of his two-decade-old reign as Bihar chief minister and setting the stage for the BJP’s long-awaited takeover in the Mandal heartland.

The development, which came in the presence of Union home minister Amit Shah, marks a striking turnaround for Nitish, sworn in as chief minister for a record 10th time barely four months ago with a huge electoral mandate obtained under his leadership.

Nitish described his sudden bid for a Rajya Sabha switch as the fulfilment of a personal ambition, but many saw it as more as a choreographed departure than a voluntary transition.

The change of guard in Bihar is likely to happen after the March 16 Rajya Sabha elections, sources said. There was no clarity from the BJP whether Nitish, who has ruled Bihar since 2005 with a brief interregnum, will be offered a berth in the Union cabinet in keeping with his stature.

Reports suggested the BJP would take over the chief minister’s post, with the JDU settling into the role of a junior partner. While current deputy chief minister and OBC face Samrat Chaudhary is believed to be the frontrunner for the top job, BJP sources wouldn’t rule out a surprise.

The JDU is expected to get two deputy chief minister posts, one of them likely to be given to Nitish’s son Nishant Kumar as a way of cushioning the pain for the ally.

“Since the beginning of my parliamentary career, I had a desire in my heart to become a member of both Houses of the state legislature, as well as both Houses of Parliament,” Nitish wrote on X.

“That’s why I want to become a Rajya Sabha MP in the upcoming election.”

Nitish has served in both Houses of the state legislature and in the Lok Sabha but never been a Rajya Sabha member.

Some BJP leaders had recently flagged the 75-year-old chief minister’s advancing age and his apparent lapses of mental acuity and awareness, while advocating an “honourable exit” for him.

Angry JDU workers, clearly reluctant to take Nitish’s post at face value, gathered outside his official residence and the party office in Patna, alleging a “conspiracy” between a party lobby and the BJP to oust their leader.

Many of the protesters argued the development had “betrayed” the huge political mandate the NDA had secured last November with the slogan “Pachis se tees, phirse Nitish”, which proclaimed a further five years for Nitish as chief minister.

The anger among the JDU ranks, including many MLAs who were taken by surprise, raised apprehensions of a split in the party, a possibility that could strengthen the BJP’s grip over the state.

Nitish tried to reassure the agitated cadres. “I assure you that my relationship with you will continue, and I will keep working for a developed Bihar. The new government will enjoy my full support and guidance,” he said.

The sequence of events bore the unmistakable imprint of Shah, widely regarded in the BJP as a master strategist.

Speculation about a change of role for Nitish had been swirling since Wednesday but few had expected it to happen so soon.

But an inkling seemed to come after Shah flew into Patna on Thursday. As his motorcade left the airport, BJP supporters showered flower petals.

Shah first met BJP national president Nitin Nabin before both of them headed to the chief minister’s 1 Aney Marg residence.

Soon after, in a calculated show of alliance unity, all three left in the same car for the Assembly, where Nitish and Nabin filed their Rajya Sabha nominations.

“Your (Nitish’s) extensive experience in public service and deep understanding of policy-making will make Rajya Sabha proceedings even more effective,” Shah later posted on X, lauding Nitish for freeing Bihar from “jungle raaj”.

“Your esteemed presence will further strengthen the NDA’s resolve of ‘Sabka Saath, Sabka Vikas’.”

The BJP’s ascendancy in Bihar’s landscape of socialist politics, long shaped by regional parties, mirrors a pattern seen in several states: the saffron party gaining a foothold through alliances with regional players before outplaying them.

The most recent example came from Maharashtra where the BJP, once junior partner to the undivided Shiv Sena, has emerged as the principal force while the Sena stands split between factions led by Uddhav Thackeray and Eknath Shinde.

Thursday’s development prompted sharp reactions from the Opposition.

Tejashwi Yadav of the RJD accused the BJP of “hijacking” Nitish while expressing sympathy for the socialist veteran.

“I had said they are making Nitishji mount the horse like a groom but someone else will take the wedding vows. The BJP has done a Maharashtra in Bihar. This is a violation of the people’s mandate,” he told reporters.

RJD Rajya Sabha MP Manoj Jha suggested that the entire script had been written in Delhi and drew a comparison between Nitish and Nicolás Maduro, the Venezuela President abducted by the US in January.

The mood was upbeat in the BJP, where leaders rushed to congratulate Nitish on his upcoming move to Parliament. Several BJP leaders privately extolled Shah for engineering a regime change in Bihar.

In contrast, heartbroken JDU workers resorted to vandalism at the party’s Patna headquarters, smashing plates that had been arranged for an event to welcome the chief minister’s son Nishant into the party.