The politics of 2018 will be about the elections of 2019. This is true of every year that precedes a general election, but since Messrs Modi & Shah live in campaign mode, it's likely to be even more the case this year. Every central government policy will be read for its electoral implications and each move in the culture wars-cow vigilantism, Ayodhya, love jihad, ghar wapasi-will be seen as a bid to turn a demographic majority of Hindus into a political bloc, to lay the electoral foundations of the Sangh Parivar's avowed goal, a Hindu Rashtra.

The eight state assembly elections scheduled for the year will be important in themselves, but they will also be way-stations to the big test of 2019. A great deal hinges on these state elections; not just general election momentum, but also the NDA's majority in the Rajya Sabha, something it lacked for the majority of its first term in office.

Of the eight states up for elections, if the BJP were to win Meghalaya, Mizoram and Karnataka and retain the states the NDA already rules, it would bring its tally of states up to 22 and reduce the Congress to two: Punjab and the tiny state-let, Puducherry. If this were to happen (and it isn't beyond the realms of possibility), Modi and Shah's goal of a Congress-mukt Bharat will have been achieved inside the BJP's first term in office.

So the Congress's improved performance in Gujarat and the rumours of Rahul Gandhi's revitalisation notwithstanding, 2018 is a year when the party faces an existential crisis in the most literal sense of that word. Its claim to be a national opposition, already threadbare given its political irrelevance in Bihar and Uttar Pradesh, will be in tatters if it were to lose Karnataka, the only substantial state it governs in south India. It could still claim an oppositional presence in many states spread over the subcontinent but, minus Karnataka, the Congress will begin to look like a politically orphaned rump, doomed to wither away in the absence of the lifeblood of office. A national party without access to lucrative office in even a single large, rich state is politically orphaned because it lacks rent-seeking opportunities to fill its electoral war chest. Given that the Congress has lost the enormous patronage that controlling the Centre once gave it, the loss of Karnataka could be fatal.

So for any political prospect, the clash in Karnataka is the most important electoral battle of 2018. This is not to say that the elections in Chhattisgarh, Madhya Pradesh and Rajasthan aren't crucial to the Congress's future in the Hindi-speaking provinces that determine any pan-Indian party's political destiny. It is to acknowledge that, without Karnataka, the Congress will have neither a bastion nor an arsenal.

Till the middle of 2016, there was a broad consensus in the media that the Karnataka government led by Siddaramaiah was weighed down by its indifferent record as the incumbent ruling party. It's worth remembering that the BJP was in power before Siddaramaiah led the Congress to a win over the BJP in 2013. One of the reasons the Congress won that election was that the BJP's vote share was seriously reduced by Yeddyurappa's defection. Yeddyurappa, piqued at being removed from the chief ministership because of serious corruption charges, retaliated by forming a breakaway party, the Karnataka Janata Paksha (KJP). The KJP won just half a dozen seats in the 2013 assembly elections, but succeeded in capturing 10 per cent of the popular vote that might otherwise have gone the BJP's way, reducing it to 40 seats in the assembly. Yeddyurappa's return to the BJP fold should help the party improve its tally but the Congress looks better placed to ward off this challenge than it did a year ago.

Some credit for this must go to the chief minister. Siddaramaiah, born into a sheep farming Kuruba family, is a latecomer to Congress politics and he has brought to the party a grassroots energy and an OBC following that it sorely missed when it was led by cosmopolitans like S.M. Krishna. The government has tended its rural constituency with a large loan waiver in 2017 and its agriculture minister Krishna Byre Gowda has aggressively promoted the cultivation of millets like ragi and bajra in response to the drought and water crisis that has made paddy and sugarcane farming impractical.

Interestingly, Siddaramaiah has adapted the BJP's use of flag, anthem and language to regional or sub-nationalist ends. He has made the case for a state flag, cast himself as a champion of Kannada and its compulsory use in education and attacked the imposition of Hindi on the state by the central government by pointedly protesting the use of Hindi signage in Bengaluru Metro stations. This, together with the fact that Karnataka continues to be amongst the top four recipients among Indian states of foreign direct investment and the hub of the country's IT industry, should give the Congress a sporting chance of retaining office in this vital state. Early polling by media organisations like Vishwa Vani and Public TV not particularly invested in the Congress suggest that Siddaramaiah might eke out a bare majority.

The problem with this scenario is that it doesn't account for the BJP's force-multiplier: Narendra Modi. Siddaramaiah won the 2013 election against a BJP government principally associated with Yeddyurappa and corruption. He will fight the 2018 election against a party that will campaign in the name of a hugely popular prime minister with a unique mastery of incendiary rhetoric and political theatre. The election will be a challenge for Modi too, a test of his ability to translate his charisma into votes in a southern state. He managed it once before in the 2014 general election when the BJP won a majority of parliamentary seats from Karnataka. Given how high the stakes are, there is little doubt that he and his lieutenant, Amit Shah, will do everything they can to repeat that success.

The main reason why the Karnataka election can't be called with any confidence despite everything that the Congress has going for it (including divisions in the state unit of the BJP) is that Modi is an unpredictable wild card, the joker in the pack. Should both parties fall short of a majority leaving Deve Gowda's Janata Dal (Secular) holding the balance of power, few people would bet against Amit Shah's ability to nobble the kingmaker.

The Gujarat election showed that the BJP has begun to lean ever more heavily on the prime minister's charisma to counteract the diminishing returns of incumbency. There is growing speculation and rumour that general elections might be called as early as the end of this year to make sure that the state elections in Rajasthan, Madhya Pradesh and Chhattisgarh scheduled for that time are held concurrently. The reasoning is that the setbacks that Vasundhara Raje and Shivraj Chouhan might suffer as incumbents in standalone state elections might be offset by the general election josh generated by Modi. Rajasthan is a case in point. Under Vasundhara Raje, the state has been something of a petri dish for right-wing economic policy and Hindu vigilantism. The Congress still has a mountain to climb; the last assembly election saw it reduced to a pitiful 21 seats in the Rajasthan assembly, but unpopular school closures, unspent budgets for social and community services and an imperious and divisive chief minister have created a political opportunity for the opposition.

In a year where the BJP holds all the cards-organisational strength, the financial resources that accrue from being the ruling party at the Centre and in a majority of states, the prime minister's charismatic ability to make the political weather-the opposition, particularly the Congress, will have to play a poor hand perfectly to avoid extinction. Should it fail in this task, the BJP's prospects in the next general election, already bright, could be radically boosted. At the risk of sounding alarmist, it's worth spelling out the political implications of a good electoral year for the BJP.

If the BJP ends 2018 as the ruling party in 22 of India's 29 states, it would be close to a two-thirds majority in the Rajya Sabha. Should it then proceed to surpass its 2014 performance in the general election scheduled for 2019, it could be close to the special majorities needed to amend the Constitution, certainly closer than any political observer could have anticipated in 2014. It is very unlikely that the BJP will win a two-thirds majority in the Lok Sabha in 2019 but very unlikely is not the same as wildly implausible. It was very unlikely in 2014 that a party with five state governments would be the ruling party in 19 states in less than three-and-a-half years, but it came to pass.

Both its supporters and its enemies believe that the BJP and its ideological parent, the RSS, are committed to literally reconstituting India. When Ananth Kumar Hegde, the BJP's five-term MP from Karnataka, announced that "we are here to change the Constitution", people paid attention despite his party's disclaimers and his own apologies. With the elevation of Yogi Adityanath to the chief ministership of India's most populous state, Narendra Modi served notice that the BJP's political project was to mainstream the feral fringe, to make the unthinkable, normal. There should be nothing startling about the notion that the BJP and its affiliates might want to formally reconstitute the Republic; the project of a Hindu Rashtra virtually requires it.

Starting in 1848, France began to mark transformative periods in its politics by giving each reworked republic, a new number. So the French are currently on to their Fifth. If the Congress and other opposition parties don't get their act together this year, Indians in 2019 might find themselves within reaching distance of a Second Republic.

-Mukul Kesavan teaches history at Jamia Millia Islamia and writes a column for the Telegraph, Calcutta