At one time, he was the poster boy of Indian politics. Not only did he slay the villain of Bihar's "jungle raj" in 2005 by rounding up lawless elements after winning an election and launching social and economic development projects, he also scored another resounding electoral victory in the company of a new set of friends, including the "villain", in 2015.
It appeared at the time that he could do no wrong. So much so that he was seen as a possible prime ministerial candidate of the "secular" front.
But, then, the rise and rise of Nitish Kumar came to an abrupt halt. He remains Bihar's Chief Minister, but the halo round his head has frayed.
The reason is not only his switching of friends in what is seen as an exercise in crass opportunism, but also his pursuit of policies which are out of sync with the modern world and threatens to reinforce Bihar's reputation for backwardness by turning the entire state into a virtual dehat or village.
The first step in this bucolic direction was the imposition of prohibition which has robbed Bihar's clubs, hotels and intellectual watering holes of cosmopolitanism. Now, Nitish Kumar has taken yet another step backwards by demanding 50 per cent reservations for the backward castes in the private sector.
To begin with the second step, it is obvious that by threatening to take the quota system to such an absurd level, the Chief Minister has scotched any hope of industrial growth in a state which is crying out for investment.
In 2012, Bihar received investment proposals worth Rs 24,000 crore. In the post-liquor ban period, they have dropped to Rs 6,500 crore.
If his new ally, Prime Minister Narendra Modi had any hope, therefore, of making Bihar the beneficiary of his Sabka Saath, Sabka Vikas goals, he can bid it goodbye.
Nitish Kumar's latest pitch in favour of the backward castes is all the more strange because he cannot seriously expect that his proposal will pass muster at the judicial level.
Like most Indian politicians, he is more interested in posing as a champion of whichever group he is courting at a given moment than in adopting measures which have a reasonable chance of success.
He merely wants to impress his targeted audience by showing that he did make an honest effort, but was stymied by the "system".
Whether it is prohibition or reservations, Nitish Kumar's ploys tend to underline crafty political manoeuvres rather than any genuine intention of acting in the state's interest.
Unfortunately for the Janata Dal (United) leader, his gambits are too palpable to deceive anyone. In the case of the reservations, it is clear that Nitish Kumar is still battling his old adversary-cum-ally-cum-adversary, Lalu Prasad Yadav of the Rashtriya Janata Dal (RJD).
Since Nitish Kumar belongs to a numerically small and politically less influential caste -- the Kurmis -- than the RJD's powerful Yadavs, he has never been at ease in Lalu Prasad's company whether at the time of their camaraderie during Jayaprakash Narayan's anti-Congress movement or when they were a part of the state government after the 2015 election victory.
The focal point of Nitish Kumar's political career has been to establish himself as the foremost leader in the state. Lalu Prasad's conviction in the fodder scam case enabled Nitish Kumar to be the No. 1 in the Janata Dal (United)-RJD-Congress government.
But he appeared to be forever looking over his shoulder to check whether he was being undermined by the RJD which has more MLAs than the Janata Dal (United).
Prohibition was the policy which he embraced to win over the lower middle class and rural women to his side. But, predictably, the liquor ban has led to an increase in drug abuse with 25 per cent of the cases in de-addiction centres now dealing with the users of cannabis, inhalants and sedatives.
Unlike prohibition which is not aimed at any caste, the demand for the 50 per cent reservations is intended by Nitish Kumar to bolster his position vis-a-vis Lalu Prasad since both are intent on playing the backward caste card.
It is also a message to his partner in the government, the Bharatiya Janata Party (BJP), about the importance of the quota system for the Chief Minister, especially when the Rashtriya Swayamsevak Sangh (RSS) chief, Mohan Bhagwat, is in favour of doing away with reservations altogether.
When Bhagwat expressed his views during the 2015 election campaign, the BJP quickly distanced itself from them for fear of losing the backward caste and Dalit votes. Even then, the BJP's reputation as a brahmin-bania party remains intact. Besides, it is now more focused on playing the nationalist card than on wooing the backward castes.
Nitish Kumar must have thought, therefore, that the time was ripe for him to up the ante on the caste issue if only to let the BJP know that he cannot be marginalised as the BJP has been tending to do since tying the knot with the Janata Dal (United).
But, whatever his intention, Nitish Kumar cannot but be aware that his position is much weaker now than when he was in the "secular" camp. Nor is there any chance that he will regain his earlier status any time in the near future.