Here, it's necessary to recall that Indira Gandhi had on that historic occasion exhibited exceptional political acumen and foresight.
As the excellent write-up here (<https://m.thewire.in/article/history/a-sataygrah-and-asatyagraha-narendra-modi-and-the-liberation-of-bangladesh>) recounts that in those critical and turbulent moments the genocidal regime of Yahya Khan had the full backing of Nixon - at the head of the US, and, also, Mao - at the helm of the People's Republic of China, India's (much bigger) next door neighbour.
The US would even mobilise its 7th fleet, spearheaded by the all-too-formidabe nuclear-powered aircraft carrier USS Enterprise in the Bay of Bengal near the Chittagong port in order to dissuade India from pushing ahead with its military intervention in the East.
India, having already concluded the Treaty of Friendship with the then USSR, in anticipation, didn't bat an eyelid.
(Ref.: <https://www.rbth.com/articles/2011/12/20/1971_war_how_russia_sank_nixons_gunboat_diplomacy_14041>.)
The rest is history.
Bangladesh became a reality on the ground.
The gang of traitors played its usual game and is now busy rewriting history.
<<The August 1971 protest launched by the Jan Sangh in Delhi, when Modi courted arrest, was to protest the India-USSR Treaty of Friendship – a treaty which gave India the diplomatic cover needed to wage war against Pakistan later that year.>>