The BJP and JDS formed a coalition government in Karnataka in 2006.
The Janata Dal Secular (JDS), stunned by its worst-ever performance in the recent Karnataka election, is leaning towards the BJP and has sent feelers for an alliance for the 2024 national election, sources say.
The JDS, which won only one of Karnataka's 28 Lok Sabha seats in the 2019 election, sent feelers to the BJP weeks after the assembly election verdict.
The Congress won a big victory in the Karnataka polls, unseating the ruling BJP and dashing the JDS' hopes of playing kingmaker. JDS won just 19 of 224 seats and was reduced to irrelevance because of a clear public mandate.
The JDS, led by former Prime Minister HD Deve Gowda and his son HD Kumaraswamy, reportedly assesses a chance to defeat the Congress and salvage its vote-base if it ties up with the BJP, its one-time ally.
The BJP and JDS formed a coalition government in Karnataka in 2006 with Mr Kumaraswamy as Chief Minister and Mr BS Yediyurappa as his deputy, under a 20-month power-sharing formula. The coalition was short-lived as the JDS did not transfer power to BJP.
There have been several indications that the JDS is once again gravitating towards its former partner.
The most striking clue was Deve Gowda's strong defence of Union Railways Minister Ashwini Vaishnaw as he faced resignation demands from other opposition parties following the Odisha train accident in which 288 were killed.
"The Railway Minister has taken all necessary steps to restore the damage that happened. He is working tirelessly. Let the inquiry be completed. The minister is doing his best and demanding his resignation at this stage is not wise," said the former Prime Minister.
Deve Gowda was also the notable exception as other opposition leaders boycotted the opening of the new parliament building.
Another giveaway was Mr Gowda's comment on Tuesday doubting the prospect of an opposition alliance against the BJP.
"I can analyse in detail about this country's politics, what is the use? Show me one party which has not associated with the BJP, either directly or indirectly. Show me one party in the whole country, then I will answer," Mr Gowda said to a question on Bihar Chief Minister Nitish Kumar's efforts to corral non-BJP parties.
Mr Gowda also avoided a direct response to questions on whether his party would join such a front. "Who is communal, who is not communal, I don't know. First of all, the definition of communal and non-communal -- it can be enlarged, then the scope is much..." he said.
Mr Gowda was also showered with birthday wishes by Prime Minister Narendra Modi and other BJP leaders when he turned 91 last month.