Not long ago, Subramaniam Swamy was an incorrigible accuser. He made the wild and unsubstantiated allegations of Sonia Gandhi being a "foreign spy" and stopped short of labelling all Muslims as traitors. These days, when he addresses the media, satraps in the government quake in their boots.

If the 2G scam is the UPA-II's nemesis, it is because of Swamy. Whenever it appears that the scam has felled its last perpetrator, the economist- cumpolitician whips out some damning document out of nowhere to put another powerful politician in the dock. Union Home Minister P. Chidambaram will agree.

The CBI filed the FIR in the 2G scam two years back in October 2009, on the directions of the Central Vigilance Commission. But the FIR did not mention any name and it pressed the pause button on its probe after registering the case.

The Janata Party chief first wrote a series of letters starting from November 2008 to the Prime Minister, drawing his attention to what could turn out to be India's biggest loot patronised by one of his cabinet colleagues, A. Raja. He received assurances from Singh but no follow-up action.

Swamy then went to Supreme Court and also filed a criminal complaint against Raja in a Tis Hazari court in December 2010. The apex court asked the CBI to prepare a detailed note on its probe and began monitoring it.

The CBI was forced to resume its probe in right earnest. Raja's arrest on February 2 this year was a logical culmination of Swamy's charges against him.

Swamy has now called for the prosecution of Chidambaram who as finance minister, he alleged, was in collusion with Raja. The government, as usual, is dismissive. The apex court has taken note of Swamy's plea and will hear the matter on October 10.

Swamy also had a hand in the recent dust-up between Chidambaram and finance minister Pranab Mukherjee. The finance ministry's secret note questioning Chidambaram's role in the allocation of the 2G spectrum came into the public domain only after Swamy placed it before the Supreme Court.