For the Shiv Sena, the euphoria of winning 18 Parliament seats this election – its highest Lok Sabha tally ever – has dissipated faster than it could have imagined. With Maharashtra’s assembly election in a few months, the party that claims to be the champion of Marathi speakers is grappling with the realisation that the Bharatiya Janata Party now has the upper hand in their Mahayuti alliance.

The tension between the two parties, which have been allies for nearly two decades, had become especially evident in the run up to Narendra Modi’s swearing in ceremony on Monday. The Sena was unhappy with being offered just one berth in the new prime minister’s cabinet, and party president Uddhav Thackeray had to be pacified over the phone by BJP chief Rajnath Singh. The Sena had hoped that as BJP’s oldest alliance partner, it would get at least three seats in the cabinet, but on May 26, Anant Geete was the only Shiv Sena MP to be sworn in as a cabinet minister.

Thackeray had also opposed Modi’s decision to invite Pakistan prime minister Nawaz Sharif for the swearing-in ceremony, and issued a statement on May 23 warning Pakistan of a nuclear attack if it did not “mend its ways”.

According to political observers, these rants and demands are just manifestations of the Sena’s growing insecurity over its status in Maharashtra after the Modi wave.

“If the Shiv Sena has won more seats than before in the Lok Sabha, it is because of Modi, not Uddhav Thackeray’s leadership,” said Mumbai-based political analyst Surendra Jhondale. Now that the Sena realises it is losing political control, Thackeray fears he might get marginalised.

“He is shouting about nuclear war only for the sake of making a statement – to tell the people of Maharashtra that while the BJP may have diluted its stance towards Pakistan, Shiv Sena’s politics is still strongly Hindutva,” said Jhondale. “Of course, it is a very shallow statement and he is only harming the Sena by making such claims.”

Given the anti-Congress mood in the general election and the fact that the saffron alliance swept away 42 of Maharashtra’s 48 LS seats, the BJP-Sena combine has a real chance of coming to power in the Maharashtra assembly as well. In such a scenario, choosing a chief minister is becoming a bone of contention between the two saffron parties, and the Sena is struggling to assert its right to the throne.

“When the alliance between the two parties came into being, it was decided that the Sena would be the Big Brother in Maharashtra, always contesting more assembly seats than the BJP,” said Prakash Bal, a senior journalist and political analyst. “But in this general election the BJP has moved ahead, and is demanding more assembly seats to show the Sena that it does not matter electorally anymore.”

This muscle-flexing by the BJP was expected, say experts, and party members also agree. “The Shiv Sena has always suppressed us in Maharashtra, even though we are a bigger, national party,” said Pooran Dave, a BJP party worker from south Mumbai. Dave believes the Sena has no moral right to complain about Nawaz Sharif being invited, given that late Sena chief Bal Thackeray had once hosted Pakistani cricketer Javed Miandad in Mumbai. “Many party workers feel that if the Sena keeps acting up like this, the BJP should just break the alliance,” he said.

Bal, however, says that the BJP cannot really afford to split from the Shiv Sena if it wants to win the majority in Maharashtra. “But the BJP will continue to put pressure on the Sena all the way up to the assembly election, till they come up with a satisfying seat-sharing solution,” said Bal.