This will go down as one of the big success stories in the annals of Indian election history. After 15 years of Congress rule, Assam voted decisively for the Bharatiya Janata Party. The BJP has gone from five seats in the assembly polls of 2011 to around 60 in 2016. Mission 64 is in the bag and the BJP alliance looks set to notch up more than 80 seats in the 126-member Assembly. Anti-incumbency does not adequately explain such a dramatic verdict. This was a campaign where the BJP got the ingredients just right.

The BJP has shown a remarkable grasp of election arithmetic, and preliminary figures suggest a spectacular vote-to-seat conversion rate. Though the Congress only managed 25 seats, it actually garnered a higher voteshare – 31% to the BJP’s 29.5% (final figures still to be released). This victory is more remarkable for its breadth than its depth. A glance at the election map shows the BJP is spread out across the state, suggesting it has managed to win a diverse mandate consisting of several different constituencies and factors. These were the four ingredients for the BJP's success in the state:

1. Familiar faces
To begin with, a party that had no recognisable faces in 2011 managed to field several big ticket candidates in 2016. After the debacle in Bihar, it wasn’t relying on the popularity of Prime Minister Narendra Modi to win an assembly election. The BJP increased its visibility partly by poaching stalwarts from rival parties with an established presence in the state.

The party's chief ministerial candidate, Sarbananda Sonowal, crossed over from the Asom Gana Parishad only in 2011. From the Congress, it culled Himanta Biswa Sarma, one of the most talented political organisers in the state and a former education minister in the Tarun Gogoi government. Both belonged to the old guard of the All Assam Students’ Union, which led the popular Assam Movement of the 1980s. More recent heavyweights from the AASU also joined the BJP ranks, bringing sizeable support bases along with them.

2. Choosing friends
Very early on, the BJP gauged that it would need to make friends to influence people and make inroads in parts of the state where local parties and politics decide elections. In the Bodoland Territorial Area District, it struck up an alliance with the Bodoland People’s Front, headed by local satrap Hagrama Mohilary. The BJP also pursued the AGP, previously considered a spent force in the state, having won no seats in the Lok Sabha elections of 2014. It was a gamble that paid off – the AGP has improved on its tally of 10 seats in 2011 and managed about five more this time around.

The “rainbow coalition” of the BJP also included tribal groups such as the Rabhas, Tiwas and Misings. Bijan Mahajan, a BJP spokesperson, attributed the victory to the “alliance of indigenous people of Assam”.

3. The pitch
The BJP was able to customise its election pitch according to its constituency. Under the larger rubric of development and “sab ka saath, sab ka vikaas”, there were subtle inflections. For instance, in the prosperous Jorhat town in Upper Assam, home to a diverse business community, the BJP held out the promise of investment and infrastructure.

Speaking in Kokrajhar, Modi promised Scheduled Tribe status to Bodos living in the hills and Karbis living in the plains. And the tea tribes, the group that is said to swing elections in Assam and a former votebank of the Congress, seems to have voted BJP. Their stated reason: the BJP promised them ST status back in 2014. Though there had been no progress in the last two years, the Congress had not moved on the matter for 15 years. Most groups felt they had good reason to vote for the saffron party.

4. Polarisation
Finally, there is the loaded question. Did the BJP win Assam through its tried and tested tactic of polarisation? After Bihar, the party dialled down its communal rhetoric. But observers detected the patterns of mainstream Hindutva in certain pockets of the state, especially areas with mixed populations – meat found in temples creating tensions between communities and local organisations of the Sangh Parivar stepping into the breach. In places like Barak Valley and Nagaon district, where such incidents were reported, the BJP has done well.

More prominently, the party chose to develop a local variant of polarisation. Politics in the state has long been shaped by the spectre of “illegal Bangladeshi immigrants”, believed to have entered the state in droves, taking over land and obliterating indigenous cultures. The BJP communalised ethnic faultlines, making a distinction between “Hindu refugees” and “Muslim infiltrators” from Bangladesh.

It worked. Across the state, people blamed the Congress for failing to weed out illegal foreigners and Bengali Hindu constituencies drew closer to the BJP. In the borderlands of Lower Assam, previously the stronghold of the All India United Democratic Front, the BJP and its ally, AGP, made surprising gains.

Doorway to the North East?

The implications of this victory are enormous. For Assam, it could signal an era of bipolar contests between the Congress and the BJP, with other parties clustered around them. For the BJP, it could be an entry point into the North East and the intensely variegated politics of the region. The party demonstrated remarkable political agility in these elections, reaching out to constituencies previously impervious to it and tapping into local issues, either directly or through allies. For the Congress, hemmed into shrinking spheres of influence, it should be a wake-up call.