A decision on telecom minister A Raja's continuance in the government may be taken after Prime Minister Manmohan Singh returns from South Korea this weekend.
But it will be taken not just on the basis of a reportedly damning CAG report on the 2G spectrum scam but also on how the Congress decides on alliances in poll-bound Tamil Nadu.
The government has been facing a lot of heat over the scam. On Wednesday, the Opposition kept up its demand for Raja's ouster in Parliament, in the wake of the comptroller and auditor general's reported indictment of the minister for causing a loss of Rs 1,76,700 crore to the exchequer.
So far, the Congress has said it intends to keep its six-year alliance with the DMK, to which Raja belongs. But this could change. Top government sources said "holding a cabinet minister directly responsible for any scam is rare. In such a circumstance, it is difficult for any government to retain the minister".
If Congress president Sonia Gandhi decides to ask DMK chief Karunanidhi to withdraw Raja, it would be a big blow to the Tamil Nadu chief minister. For, while he is dependent on 34 Congress MLAs to run his minority government, he has also steadfastly resisted axing the Dalit minister.
This may also damage the DMK further by widening the rift between Karunanidhi's sons and Raja, party sources said.
As for the Congress-led UPA, it is backed by an 18-strong DMK group in Lok Sabha. If the DMK walks out, its rival, the AIADMK - with nine members - won't hesitate to take its place.
However, sources close to central DMK ministers said Karunanidhi is yet to feel the Congress heat.
"He does not know whether the Congress wants Raja out," said one DMK official.
In case of an adverse DMK response, the Congress may have the option of either aligning with the AIADMK or with actor Vijaykanth's DMDK, both of which seem willing.
A third option would be for the Congress to go it alone, which is backed by supporters of home minister P Chidambaram, who wish to see as the chief minister candidate.