The Indian government is scrambling to build political support for a controversial landmark nuclear energy pact with the United States.  But communist allies have warned they will bring down the Congress-led government, if it goes ahead with the nuclear deal.  From New Delhi, Anjana Pasricha reports on efforts being made to resolve the impasse.      

The political spat that is threatening the Congress-led government began after Prime Minister Manmohan Singh says he wants to push through a civilian nuclear deal with the United States, so that it can receive approval of the U.S. Senate before President Bush leaves office in January.

Singh's communist allies immediately warned they will withdraw support, if the government goes ahead with the pact.

The nuclear deal was clinched in 2006.  It would allow India access to civilian nuclear technology, even though it has not signed the nuclear non-proliferation treaty.

But the deal has been in limbo because leftist parties, who staunchly oppose the pact, have not allowed the government to seek approvals needed to make it operational.  They say the pact will build a strategic partnership with the United States and damage India's independent foreign policy.

The government and the leftists are scheduled to meet Wednesday to see if they can resolve the impasse.

Independent political analyst, Mahesh Rangarajan, says the meeting will be crucial, and could spell the "end-game" for both sides.  

"Both sides seem firm," he said.  "The left position is unchanged and, over the last few weeks, the prime minister and the Congress president have indicated that the government is very keen to go ahead with the last stages of the [nuclear] deal, so unless one of them gives way tomorrow, we may well see a parting of ways."

Analysts say the government now faces a stark choice.  It can either push ahead with the nuclear pact and risk early general elections or virtually shelve a deal which it has described as an important initiative.     

The head of the Congress Party, Sonia Gandhi, has held several rounds of meetings with other allies in the coalition government, in a bid to shore up support for the nuclear pact.      

Most political allies say they support the nuclear pact, but do not want to go to the polls at a time when inflation is running at nearly 11 percent.

Meanwhile, Washington has warned that time is running out for the deal, which still needs approval from groups like the International Atomic Energy Agency, before it can go to the U.S. Senate.