As rightly pointed out, the spectrum of national politics has taken a new turn since the outcome of the Northeast Assembly elections, where the BJP won the Tripura Assembly with a landslide and retained power in Meghalaya and Nagaland in coalition with the regional parties. Galvanised by the BJP's stunning victory in the North-East, the opposition parties once again came around to the need of implementing unified efforts on their part to put up a credible challenge before the lotus party. Taking a step in that direction, Bahujan Samaj Party supremo Mayawati had lent last-minute support to the Samajwadi Party candidates in the Gorakhpur-Phulpur Lok Sabha by-elections and both the SP candidates trounced their BJP rivals in an equally stunning victory for the opposition. The losses for the BJP in the two prestigious Lok Sabha seats represented by Chief Minister Yogi Adityanath and Deputy Chief Minister Keshav Prasad Maurya were further accentuated by a similar defeat in the Araria Lok Sabha by-election and Jehanabad Assembly by-polls in Bihar. Both seats were won by Lalu Prasad's RJD while the BJP won the Bhabhua Assembly election. In a nutshell, BJP conceded four out of five seats that went to by-polls in Uttar Pradesh and Bihar. This signals that caste-based alliances can still give BJP a tough fight in the two crucial states of Uttar Pradesh and Bihar. UP Chief Minister Yogi Adityanath admitted having misunderstood the caste alliance between Mayawati and Akhilesh Yadav. He also admitted that BJP was overconfident about its victory and that became an important reason causing its defeat in the two prestigious Lok Sabha seats. But, more notably, this election brings back Mayawati in the reckoning. Her sway on the voters was unmistakable. Even Samajwadi Party leader Akhilesh Yadav profusely expressed his gratitude for Mayawati's support. Mayawati's BSP had won no seats in the 2014 Lok Sabha elections and it won only 19 seats in the UP Assembly elections held last year. The two leaders had been on the margins of national politics after their defeat in the UP elections. Now, with their victory in the Gorakhpur and Phulpur Lok Sabha seats, the two parties will lead the efforts of a grand alliance of opposition parties ahead of the 2019 Lok Sabha elections. There are a number of Assembly elections lined up this year, where opposition parties can experiment with their unification model. Telangana Chief Minister K Chandrasekhar Rao has expressed his desire to play a more active role in national politics and has floated the idea of a People's Third Front, a political front of non-Congress, non-NDA parties. West Bengal Chief Minister Mamata Banerjee has called upon regional parties to forge an alliance against BJP. NDA partner Telugu Desam Party (TDP) has already flagged its differences with BJP and the Centre for not according a special package to Andhra Pradesh. It has also pulled out two ministers from the Union Cabinet. Though the TDP is still a part of the NDA at the Centre, its relations with BJP in the state are on the rocks. Further, two BJP ministers in the Chandrababu Naidu Cabinet have resigned from their posts. An Assembly election is due next year. Problems are also being routinely floated from another NDA partner, Shiv Sena, which has been flagging their disappointments from the state as well as the central governments. If the disgruntled TDP and Shiv Sena join the opposition's grand alliance in 2019, the likely scenario of all opposition parties coming together to present a united fight to the BJP and its PM candidate Narendra Modi could be unnerving for the BJP. But, before that, the opposition needs to show some results. Next is the Karnataka Assembly election, due in April-May. The BJP will try to wrest power in the state from the incumbent Congress. If the opposition joins forces with the Congress to defeat BJP in Karnataka, it will play a decisive role in the idea of forging a grand alliance of opposition parties. BJP is in power in 20 states and three of its major states are going to polls this year: Chhattisgarh, Madhya Pradesh, and Rajasthan. In similar by-elections in Madhya Pradesh and Rajasthan, the Congress candidates have defeated their BJP rivals. How much BJP is troubled by the opposition in these states will depend on how well the opposition is able to orchestrate a united fight. The latest by-election results bring the opposition at the epicentre of the impending electoral battles.