Siwan's terror Mohammad Shahabuddin means to Lalu Prasad what Rampur strongman Azam Khan means to Samajwadi Party chief Mulayam Singh Yadav in Uttar Pradesh.

More than his ability to strike fear into people's hearts, Shahabuddin's clout in his party stems from his frenzied following in his community, which constitutes over 16 per cent of the state's population. Mulayam, too, is believed to have similar compulsions with Azam Khan.

Soon after coming out of the Bhagalpur jail on bail on Saturday, Shahabuddin trained his guns on Nitish Kumar and said Nitish as chief minister was the "product of circumstances". Some RJD leaders, too, backed Shahabuddin in his tirade against Nitish.

The chief minister returned fire on Sunday, describing himself as the "CM with popular mandate". JDU spokesman Neeraj Kumar declared: "A history sheeter (Shahabuddin) is advising on politics after coming out of jail after 11 years. Shahabuddin was convicted and charge-sheeted in numerous cases of grave crime. He has no right to speak to Nitish ji who stands out for his fairness and sense of justice."

Tthe verbal duel between the two major ruling allies - the JDU and the RJD - is stoking the perception that the JDU-RJD relationship might become a casualty of the clash.

Lalu, who was in Delhi recently for a health check-up and is learnt to have been travelling in western UP, has preferred to stay mum on the verbal duel between Shahabuddin and Nitish. How far will the acrimony between Shahabuddin and Nitish go? To what extent will Lalu, who thrives on the M-Y (Muslim-Yadav) combination, back Shahabuddin in the tirade against Nitish? Does it have the potential to rock the boat of the JDU-RJD coalition?

A Delhi-based RJD leader close to Lalu said: " Baadal jitna garazta hai, utna barasta nahin (The cloud doesn't bring rain in proportion to how much it thunders)."

A senior RJD and JDU strategist cited three reasons to argue that the Shahabuddin-Nitish spat had little potential to effectively damage the Nitish-Lalu friendship: First, if the JDU-RJD relationship goes awry, its foremost casualty will be the fledgling political career of Lalu's sons Tejashwi and Tej Pratap, which the RJD boss can ill afford because he has been stripped of the right to contest the polls in the wake of his sentencing. Second, Lalu'a calm calculator behind his carefree disposition knows it well that despite his larger base, his party had barely 24 MLAs in the previous Assembly and suffered repeated defeats at the hands of the Nitish-led NDA since 2005. Moreover, Lalu, a player of M-Y politics, cannot afford a tie-up with the BJP. "If Lalu attempts to destabilise Nitish it will be suicidal for Lalu whose family is at stake in the current ruling dispensation," said a Lalu confidante.

Third, given the situation the JDU, RJD and the Congress are in, Nitish too has no way out. He has taken his battle with the BJP that is under the stewardship of Prime Minister Narendra Modi too far and is left with few options to rule Bihar without the RJD.

"There is no way out either for Lalu or Nitish other than sailing together, at least till the 2019 Lok Sabha polls," said a JDU strategist.

"The compulsion that brought Lalu-Nitish together is very much there. They have to stay together if they have to stay in power."