The fragile unity of the opposition was shattered for the second time in a week when three parties broke ranks with the Congress and joined a government function to roll out the goods and services tax (GST).
The Nationalist Congress Party, Samajwadi Party and the Janata Dal (United) attended the glittering event that began on Friday night and stretched past midnight at Parliament's central hall.
The Congress, Left parties, DMK, Trinamool Congress and some others boycotted the event, calling it a self-promotion exercise of the government.
President Pranab Mukherjee and Prime Minister Narendra Modi pressed a button to implement India's biggest tax reform since Independence that will unify the country with a single tax, though with different slabs.
NCP's Sharad Pawar and SP's Ram Gopal Yadav were seated in the front row, along with BJP chief Amit Shah. Shah was seen talking to Pawar through most of the event.
CPM's Asim
Dasgupta, a former West Bengal's finance minister who headed the GST committee in 2000, was also present.
The government requested the Congress and other opposition parties to attend the event, but it did not cut much ice with them.
"A reform that holds great potential is being rushed through in a half-baked way with a self-promotional spectacle #GSTTamasha," Congress vice-president Rahul Gandhi tweeted.
The Congress position, however, did not impress its ally, the NCP.
Pawar was present when UPA nominee Meira Kumar filed nomination papers on June 28, but went along with the JD(U) to take an independent line on GST.
The JD(U) of Nitish Kumar had broken ranks with the opposition earlier this week to support NDA's presidential candidate Ramanath Kovind.
Even the Samajawadi Party, which lost Uttar Pradesh to the BJP in this year's assembly election, dropped its initial reluctance and attended the GST event.