The Aam Aadmi Party's astonishing success in Delhi, where it won 28 seats in the election and eventually went on to form the government in late December, has many worried. The BJP is alert to this threat, but does not as yet have a clear strategy to tackle it, said experts.

AAP announced on January 15 that it planned to contest 400 of the 545 seats in the Lok Sabha in the general election due this year. It is clearly raring for a fight in the national poll. With the Congress' dismal performance in the assembly elections conducted in Delhi, Rajasthan, Chhattisgarh and Madhya Pradesh, the BJP's real contender is AAP, said commentators.

Some commentators and politicians are sceptical of AAP's ability to scale up so quickly after the Delhi poll. But despite this, the BJP is wary of the party, mainly because of the new political language it is speaking.

AAP, whose discourse focuses on corruption and the apathy of the ruling elite, is painting both the Congress and the BJP in much the same light -- as compromised national parties that rob the common man of his voice and his money.

It is no wonder then that senior leaders of both the BJP, and its ideological affiliate, the Rashtriya Swayamsevak Sangh, have come forward to acknowledge AAP as a challenge, and even take potshots at it.

Veteran RSS leader R Govindacharya, despite having been eased out of the BJP, is just the latest in a series of current or former leaders of the BJP and its affiliates to publicly discuss or attack the AAP.

Govindacharya on Thursday claimed that Delhi chief minister Arvind Kejriwal had in the fight against corruption developed close links with organisations that were RSS-backed. AAP leaders denied this link, however, saying that the party did not even exist when Kejriwal had collaborated with RSS-backed groups.

A month ago, RSS leaders met senior BJP leaders Nitin Gadkari, Ram Lal and Rajnath Singh and chided them for criticising AAP instead of learning from its grassroots-based campaign policy.

On Monday, the BJP's prime ministerial candidate, Gujarat chief minister Narendra Modi, attacked the Delhi government for the murder of an Assamese youth by a drunken gang in the city and for the alleged mistreatment of Ugandan women in the city's Khirki Extension on January 15, when the state law minister led a raid in the area to crack down on an alleged prostitution racket.

"The BJP is obviously threatened by the AAP, and hence, is hostile to it," said Ajay Bose, a political commentator based in Delhi. This hostility was despite the RSS advising the BJP to take a leaf out of the new party's book.

"Unlike AAP, which garnered grassroots support through pavement pounding during the Delhi election campaign, the BJP, in many areas, does not have much of a grassroots network," he said.

Perhaps because of this lacuna, the BJP was focusing on a personality-based brand of politics, with Modi looming large in its plans for the national election.

Modi has the backing of the corporate sector, and hence the media, according to Bose. "He is bigger than the RSS in many ways," Bose said. Thanks to these factors, Modi is still the best bet for the BJP and the RSS.

But backing Modi leaves the RSS's kar sevaks with the task of drumming up support for the BJP from the grassroots. In this context, it is easy to see why the RSS is taking the growth of AAP seriously -- AAP, after all, is its competition on the streets.

RSS was not buying the Modi bubble, said Bose. But they would back him, and hope their cadres will be able get the lower middle-class and working-class vote for the BJP.

But while the RSS takes AAP's street cred seriously, AAP finds its image tarnished in the corporate-controlled media, which gives Modi his due share of hype.

"There is a clear slant to the reporting in the Khirki incident," said Bose.

"Why weren't Khirki residents quoted? They would have been able to confirm that a brothel was indeed there," he said.

So, on the one hand, the BJP fears AAP's grassroots presence, but could be taking solace in its sinking fortunes in the media.

But AAP is also not without challenges more serious than a capriciousness of media adulation. By planning to contest more than 400 seats, it could be seen as stretching itself too thin. Its strategy appears to be developing a network of concerned NGOs and activist groups, all fired up by the unexpected success of AAP in the Delhi poll, who will canvass grassroots support across the country.

This could easily fail, simply because of time constraints, and surely fail if there is no larger plan.

"But there is a plan. AAP could abandon government in Delhi and fight on a national scale with Kejriwal and the successful Delhi teams," said Bose.

Nilanjan Mukhopadhyay, senior journalist and Modi biographer, said that the BJP would not be able to tackle AAP without two key moves. They will need to enlighten the public about AAP's detrimental economic policies, such as free water and electricity at half the price, and Modi should develop a clear strategy to tackle the new party.

"The AAP are new, but they are not political novices," said Mukhopadhyay.

This was because they had great appeal to the working-class and lower middle-class voter, who wouldn't necessarily pay heed to scams running into the thousands of crores, but hated the petty, daily corruption of the police force and the bureaucracy.

Hence, Somnath Bharti's vigilantism and Kejriwal's dharna-mongering, despite being unbecoming of a statesman (though appropriate for an agitator), were quite popular with the vote bank they so adroitly harnessed for the Delhi poll.

"Agitators usually don't become good statesmen. Look at Uma Bharti, or Mamata Bannerjee. But the AAP bucks even that trend," he said.

The only way to counter this was to make the campaign for the election an exercise in coaching the public to take a closer look at the simplified narrative of corruption they had imbibed from the AAP.

Also, Modi would have to come up with a better strategy to tackle AAP rather than attack it for the death of Nido Taniam and the alleged harassment of Ugandan women.

"Modi appears to be watching and waiting for them to make a mistake," he said.

But hadn't AAP already started making its mistakes, given the negative coverage of the Khirki incident?

"Yes and no. They are still in agitation mode, thereby undermining the institutional fabric of the country, but it appeals to their vote bank," he said.

To the lower-class worker charged with AAP success, putting pressure on the police is actually a welcome sight. This is why the BJP had no choice but to take the fight to the streets, with the RSS, so that the public's perception of AAP would change.

But this would also mean that the BJP would have to shift from its personality- and identity-based politics, and imitate AAP by moving away from religious identity and turn the campaign into something about issues.

"Every campaign is also a tutorial," said Mukhopadhyay.

In this case, probably for both the campaigner and the voter.