The leaders of the opposition have decided not to name anyone for the PMs post before the elections. They will join hands first to trounce the BJP at the hustings and most probably the single largest party emerging out of the opposition will get the chance to nominate the name for the PMs post in case if they are in a position to do so.
The concentration will be to make alliances first and jointly get organised to fight against Modi. Mamatha Banerjee the TMC leader is also rallying around the leaders of the opposition for the January 19 rally where the opposition would show off the strength against the BJP. Meanwhile, the mother of Congress President has decided not to contest the elections this time. Even Priyanka Gandhi the sister of Rahul also wants to be a strategist for the campaigning and see that Congress emerges as the single largest party in 2019.
But the Modi-Shah Jodi is pretty confident that they would come back to power in 2019. There are 3 states that would go for the election and the Congress again decided not to name anyone for the post of CM.
It is possible that they might go for the Karnataka experiment again if there is any chance to stop the BJP in these 3 states. If the BJP gets 2 states, then the opposition can forget about 2019. If the Opposition goes to polls without naming anyone for the PMs post, then Modi will easily come to power again. Unable to name the PM itself means that there is no consensus for the time being.