Bihar chief minister Nitish Kumar has always punched well above his electoral weight in national politics. It has to do with his image as a rare serious politician, a doer with a clean image and reputation - a rarity in Indian politics.

Today this image has come back to haunt Kumar who does not brook any compromise with his projection as the "Mr Clean of Indian politics". His uneasy alliance with Lalu Yadav and junior partner Congress for the grandiosely titled "mahagatbandhan" and the serial corruption cases against the Yadav clan including Kumar's deputy Tejaswi Yadav are today a millstone around Kumar's neck.

Yet, intriguingly, sources tell me that the alliance is safe as the junior partner Congress has put the onus of the entire Opposition unity collapsing on Kumar and there being no united front to take on uber Modi who looms over the 2019 general election.

Earlier, Kumar had emerged as the fulcrum of uniting the Opposition after he and Yadav had stopped the Modi and Amit Shah electoral juggernaut in Bihar. Kumar grew increasingly disenchanted with the ramshackle Opposition led in the most lackadaisical manner in the Congress by Rahul Gandhi.

Kumar's defection to the NDA on the candidature of president-elect Ram Nath Kovind dealt a body blow to Opposition unity. Yet, Kumar was unrepentant, saying the Opposition took too long to get their act together and instead of clever politics was only playing "me too" and "reactive politics".

Kumar said the Opposition lacked any "coherent agenda" expect for a visceral anti-Modi chant and clearly the public was not buying it. Kumar, the shrewdest politician of his generation, had earlier broken ranks and supported Modi’s demonetisation last year.

Now, though he does not want to be seen as the man who sank the secular boat, Kumar knows the Opposition is in a shambles, yet he does not want to be the fall guy (preferring it to be Rahul Gandhi) who ensured that the Opposition could not take on Modi.

Sources say Lalu, in his one conversation with him, rubbed in with great conviction as to how history would not forgive Kumar if he took BJP support to run the Bihar government. Interestingly, Lalu even told him that "bhakt media has taken a supari against his (Yadav's) family and the allegations do not impact Bihar politics at all".

Kumar as is his wont stayed silent and digested what his comrade-turned-bête-noire-turned-ally said. He also has a cushion of only two MLAs if he decides to bite the bullet and throw in his lot with the BJP.

Lalu knows he has to bite the Tejaswi bullet, yet his family prevails each time it comes to the crunch, say sources. Photo: PTI

Kumar is also nervous about the aggression displayed by the BJP and contentious outfits of cow vigilantes which are currently setting the agenda. Kumar knows the sizeable Muslim vote that he gets in Bihar will be torpedoed if he throws in his lot with the BJP.

Even within the JD(U), while a facade of absolute unity is being maintained, sources say a section of the party is restive, specially the Muslim legislators, and will openly rebel if Kumar ties up with the BJP.

Kumar and Modi have always been frenemies. Both are extremely ambitious and quite similar in never questioning their own judgment. Kumar knows the BJP’s open offer of support is a poisoned chalice - it will finish him in Bihar politics and enable Shah to effect a devastating BJP script for the next Bihar elections.

A senior JD(U) leader tells me: "Nitish knows Modi has neither forgiven him nor forgotten the cancelled dinner when they were still allies, or even the Gujarat aid cheque sent for the Bihar floods which Kumar returned." Neither has Kumar forgotten how Modi tried to use him to burnish his image.

Currently, Kumar is doing a delicate tightrope walk. When he meets Rahul Gandhi, he reminds him of the ordinance Gandhi tore up which would have enabled Lalu to contest the elections. Kumar speaks longingly of "sushasan" (good governance) and nudges Gandhi into making Lalu do the right thing of making his son resign to spare Kumar the blushes.

Kumar deftly got out of meeting Sonia Gandhi who he believes has a soft corner for Lalu – he was the first leader to support her entry in Indian politics - and chose to meet junior Gandhi instead.

It is really up to the Congress and its wobbly leadership to ensure that Lalu blinks first and a way out is found for Kumar.

One of the plans includes all Bihar ministers resigning and RJD giving outside support. Alternatively, Lalu could look outside his large family and make a Muslim legislator the deputy CM. This is Kumar's favourite way out and the one he urged Gandhi to get Lalu to follow.

Lalu knows he has to bite the Tejaswi bullet, yet his family prevails each time it comes to the crunch, I'm told.

Some people tell me that tearful scenes and fights have been the order of the day in the Lalu household, with mother Rabri Devi absolutely against the idea of her "bitwa" (son) quitting. Members of the Lalu family believe that any resignation would be tantamount to an admission of guilt and that it is apparent to the Bihar public that Modi is on a witch-hunt against the Yadav clan. A dramatic martyrdom gesture by Tejaswi at next month's mammoth rally is still not ruled out.

The Congress does not want to upset Lalu who has been a vociferous supporter and also does not want to alienate Kumar who gives the Opposition some badly needed credibility. It's trying to make both sides come around.

Kumar had planned to run a successful state government and wanted to lead the Opposition in 2019. Currently, he is fighting to make sure he is a contender.

Also read: 7 reasons why Nitish Kumar must not surrender to BJP despite raids on Lalu