National Democratic Alliance-backed independent candidate Bhairon Singh Shekhawat's campaign leaders on Tuesday said the political future of the Third Front at the national level was at stake after its abstention call in the presidential polls, terming the move as an "unpardonable offence."

"Remaining neutral when you are expected to take sides is an unpardonable offence, which gets recorded in history," said Shekhawat's spokesperson Sushma Swaraj, who claimed that the Third Front's move does not lie in the interest of the parties that are part of the grouping.

She wanted the front to reconsider its decision.

Her comments at a news conference in Delhi came a day after senior Bharatiya Janata Party leader Lal Kishenchand Advani petitioned the Election Commission to declare as unconstitutional the decision of the United National Progressive Alliance or the Third Front to abstain in the presidential elections.

In a stinging remark, Swaraj insisted that UNPA leaders would have to be either with the Congress or with the BJP in order to be in the reckoning at the national level.

"You can do this (non-BJP, non-Congress) politics in regions. But at the national level, you will be required to take a position either way," she said adding, the UNPA's move would strengthen the Congress.

"With your present position, you can do conclaves, but not politics," she remarked.

Swaraj, however, claimed that Shekhawat would surely win Thursday's elections despite the UNPA's abstention.