The BJP and Nitish Kumar appear to be coping with the post-traumatic stress syndrome of their break-up by swapping unfettered attacks.On Sunday, BJP president Rajnath Singh warned Mr Kumar, the chief minister of Bihar, that his party could be "wiped out of Indian politics." (Read) Today, Mr Kumar retaliated, "If I decide to reveal what I know, a lot of people will be in trouble."A week ago, the BJP and Mr Kumar's party, the regional powerhouse Janata Dal (United) or JD(U), ended a 17-year alliance.Mr Kumar said the split was impelled by the BJP's decision to promote Narendra Modi by placing him in charge of its national campaign. The JD(U) says Mr Modi, the chief minister of Gujarat, is a divisive leader who did not do enough to stop hundreds of Muslims from being killed on his watch in 2002.The BJP chief said today that "some parties appear to be suffering from secularitis," a swipe at the Bihar chief minister.

Mr Kumar won a trust vote last week in the Bihar legislature, with support from the Congress. Both sides have denied that this is an omen of a larger political partnership. But at a rally in Patna yesterday, the BJP chief warned the chief minister that a collaboration with the Congress would lead to his political extinction.Mr Kumar has said that Mr Modi's new role suggests he is being primed for his party's prime ministerial nomination, which is unacceptable to the JD(U).