It was the insult heaped on him by the Congress party under Sonia Gandhi's leadership that made him so bitter against Gandhi fanily especially the Congress president.
In one of his interviews after the excerpts of his forthcoming book was made public, Natwar went to the extent of saying that some part of Sonia Gandhi is not Indian because no Indian would have treated him so shabbily as Sonia Gandhi did.
“Neither Jawaharlal Nehru, Indira Gandhi nor Rajiv – nor any other Indian - would have behaved like that (with me). That is a part of Sonia that is ruthless,” said Natwar Singh.
When asked if Sonia's behavior was because of her Italian origins, Natwar Singh said, “What else can it be? Some part of her is not Indian”.
