In what was seen as a body blow to the Opposition unity in Bihar, Nitish Kumar resigned as Bihar Chief Minister on July 26, 2017. He cited "irreconcilable differences" with ally RJD on the issue of corruption charges against his then-deputy Tejashwi Yadav. The BJP swiftly moved in, praising Mr. Kumar’s action, and giving its letter of support to a government headed by him.
On July 27, 2017,Mr. Kumar took the oath as the Chief Minister of Bihar, this time, however, with the support of the BJP.
A look at the political career of Nitish Kumar through the years
1985: Nitish Kumar elected to the State Assembly
1989: Backs Lalu Prasad in bagging the chair of the Leader of Opposition
1996: Switches loyalty to BJP
From 1998 to 2004: He served in the NDA government under A.B. Vajpayee in various capacities as the Railway,Surface Transport and Agriculture Minister
November 2005: Became Bihar Chief Minister with the BJP as the coalition partner
June 2013: Broke alliance with the BJP when it was clear that Narendra Modi was the BJP's prime ministerial candidate
February 2015: Allies with Lalu Prasad and contests the Assembly election, forming grand alliance with the Congress
July 2016, 2017: Takes another U-turn, decides to ally with the BJP to form the government in the State. Takes oath as Chief Minister for the sixth time, this time with the BJP's help