File photo of Nitish Kumar

Nitish Kumar, who resigned as Bihar chief minister owning moral responsibility for his party's rout in the national election, today congratulated Narendra Modi. "I congratulate him on his victory and wish him all the best as the Prime Minister,'' Mr Kumar said in a facebook post.Mr Kumar's decision to end his Janata Dal United party's 17-year alliance with the BJP over the elevation of Mr Modi is being seen as a major reason for its poll drubbing.The BJP's Sushil Kumar Modi, Mr Kumar's former deputy, tweeted, "Still Nkumar doesn't have courage to telephone @narendramodi & congratulate him.At least he has used FB to wish him.So jealous? (sic)"Since the alliance ended last June, the two leaders have exchanged a series of acerbic barbs, which only turned progressively vicious during the campaign for the Lok Sabha polls.A series of bomb explosions targeting Mr Modi's rally in Patna on October 17, in which six people were killed, added to the bitter war of words. The BJP leader accused Mr Kumar of reducing Bihar into a "hub for terrorists,'' and failing to protect citizens.The former Bihar chief minister retaliated, comparing Mr Modi to Hitler. "This is not how democracy works. This is the language of Hitler, of a person who brooks no opposition,'' he told a party conference at Rajgir on October 27.The Janata Dal United has won just two of Bihar's 40 seats in the polls that saw a massive mandate for the BJP and Mr Modi, its prime ministerial candidate. In Bihar, the BJP won 31 seats along with its allies.After Mr Kumar's resignation, a new Chief Minister named by him, Jitan Ram Manjhi, has taken charge.Though he accepted the blame for his party's defeat, Mr Kumar insisted that his decision to sever ties with the BJP was right."We took a principled stand as it was not possible, ideologically, to continue the alliance," he said.

In 2009, the JD(U) had won 20 of the 40 parliamentary seats in Bihar, while its partner BJP had walked away with another 12.