While Narendra Modi's diatribes at a Bharatiya Janata Party (BJP) meeting - he compared the Congress with termites - reflected the customary crudeness of his cyber supporters, Prime Minister Manmohan Singh's riposte in parliament was reminiscent of his combative comments on the eve of the 2009 general election.

At that time, he had countered L.K. Advani's charge of being weak by recalling how the BJP leader moped in a corner while his riotous followers demolished an ancient mosque. This time, too, Manmohan Singh taunted the BJP by predicting that the failure of the party's "lauh purush" (iron man) to dislodge the Congress will be repeated in 2014.

The prime minister's other jibe directed at Advani in 2009 was to change his astrologers. Now, with just about a year to go before the next big electoral test between the two major parties, those who peer into the future will be hard put to find out which of the two have an advantage.

Only one thing is clear. While the Congress has squandered the lead provided by the 200-plus seats it won in the last election, the BJP hasn't been able to step into the breach. One reason for its failure is that it hasn't yet been able to fill the vacuum created by Atal Behari Vajpayee's retirement.

Shortly after the 2009 defeat, Advani's willingness to be leader of the opposition alerted the BJP to his desire to be a prime ministerial candidate again. To abort this possibility, the party kicked him upstairs by making him chairman of the party parliamentary board and appointing Sushma Swaraj as leader of the opposition in the Lok Sabha.

The belief at the time that the number of prime ministerial aspirants had been brought down to two - Sushma Swaraj and Arun Jaitley - was however negated by Modi's decision to throw his hat into the ring.

Even if none of this is formally articulated by the BJP, the suggestions of its partners in the National Democratic Alliance (NDA) provide enough indications about the prospects of the front-runners.

For instance, while Bihar Chief Minister Nitish Kumar has expressed his reservations about Modi obviously because the latter's nomination will scare away large sections of the minorities - Muslims and Christians - the Shiv Sena has voiced its preference for Sushma Swaraj presumably because, as a party of Maharashtrians, it will not like a Gujarati, viz. Modi, to be prime minister.

It may be recalled that in the presidential election of 2007, the Shiv Sena had voted for the Congress' Pratibha Patil, who is a Maharashtrian, instead of the BJP's Bhairon Singh Shekhawat. This time, too, the Sena - and the Janata Dal-United (JD-U) - opted for the Congress's Pranab Mukherjee. Evidently, when it comes to making a major choice, the BJP's friends prefer to go their own way on communal, personal (in the case of Mukherjee) and provincial considerations.

For all the cheers that Modi receives, therefore, at the BJP's conclaves, the chances of the party finally choosing him are not too high since it will create unmanageable cracks in the NDA. The Congress' none-too-subtle overtures to Nitish Kumar with assurances of considering his demand for a special economic status for Bihar are not without significance in this context.

But, it isn't only the BJP which is unable to decide on a prime ministerial nominee. Although Rahul Gandhi's elevation to the post of Congress vice president seemingly confirmed the belief that he will be the candidate, the heir-apparent himself has been hesitant.

His latest ruminations in parliament's central hall echo what he said at the Congress' last Jaipur conclave about the party functioning without rules and decisions being taken behind closed doors. While emphasising his bottom-up idea of empowerment although he himself has parachuted down from above, Rahul has however clarified that since he is "not in politics for the sake of power", becoming prime minister "is not a priority" for him.

It is not clear whether he is serious. Or whether there is a game plan behind his renunciation like his mother's in 2004 when she chose Manmohan Singh for the post after refusing to accept it herself.

There is little doubt, of course, that the Congress will follow whatever path is laid down for it by the dynasty. It is possible that Manmohan Singh will be named again on the eve of the polls. Or the matter will be kept open for the newly elected MPs. Or Rahul himself will decide to take the plunge.

For the Congress, much will depend on how the economy fares. An upturn will probably see Manmohan Singh for another two years. A downturn may induce the party to play the Rahul card.

For the BJP, there are two worse case scenarios. One is that Modi's selection will make the NDA fall apart, and the other is that Modi's rejection will turn the Gujarat strong man into a dangerous rebel.