He said a "Modi-centric" campaign "lacked credibility" because of the unkept promises of the past and blamed BJP's "divisive tactics" for the drubbing.
Shourie, a minister in the Vajpayee government, who is no longer with the party, accused Shah and Jaitley of "fomenting" a coalition against Modi by forcing the other opposition parties, which commanding over 69 per cent of vote, to get into an alliance.
He said that the BJP came to power at the height of Modi's popularity with merely 31 per cent votes.
"It is Modi, the master strategist (Shah) and Jaitley," he said when asked who should be held responsible for the
defeat. "There is no fourth person in the party or the government."
Asked what went wrong with the party's Bihar campaign, he said, "everything".
Elaborating his comments, he said "a Modi-centric campaign, a divisive campaign and the campaign lacked credibility as promises of the past have not been kept".
In this context, he referred to Modi's claim during Lok Sabha poll campaign that everybody will get Rs 15 lakh with the amount of black money he would bring to India if he was voted to power.
And then their party president said it was a 'jumla', so people will obviously not take you seriously when you make new promises, he added.
Asked about the implications of the loss for the party and the government, he said, "The silent non-cooperation movement against them (Modi, Shah, Jaitley) will deepen. In the government, bureaucracy will also not be forthcoming."
Once an avid supporter of Modi, Shourie has turned a sharp critic of his government and the party.