India's governing Congress Party was on the verge of swapping allies on Friday in a last-ditch effort to push through a nuclear deal with the United States.

The Congress Party was on the brink of replacing its leftist allies, led by the Communist Party, with a coalition led by the Samajwadi, a North Indian socialist party. The Congress Party’s grip on India is weakening as inflation and fuel prices rise and the economy slows, and securing an ally is crucial to staying in power.

Prime Minister Manmohan Singh, who has been a staunch supporter of the nuclear agreement with the United States, has been rushing to firm up support for the deal in India ahead of the G8 summit meeting in Japan, which starts on Monday.

There, he is expected to meet with President Bush to discuss the arrangement, which would grant India access to American nuclear technology and atomic fuel in exchange for agreeing to international inspections of its reactors.

The proposal has dominated headlines and fueled heavy debate almost since it was put forward in 2005. Critics, including the Communist Party, say the deal ties India’s future foreign and energy policy too closely to the United States, but advocates say it could usher in a new era of nuclear power in India, freeing the country from heavy dependence on fossil fuels.

American companies have been lobbying heavily for the deal, hoping to sell nuclear power-related equipment to India.

Mulayam Singh Yadav, the founder and chief of the Samajwadi Party, told reporters early Friday that Mr. Singh’s explanation of the proposal was “satisfactory,” signaling that his party could support it. As of Friday evening, the Samajwadi Party had not officially agreed to support Congress or the nuclear deal, but its backing was widely expected.

If Mr. Singh’s Congress Party fails to secure Samajwadi’s support, it will probably be forced to call early elections, in which it is expected to lose many representatives in Parliament because of growing concerns over inflation and high oil prices. Samajwadi has 39 seats in Parliament, while the Congress Party’s former Communist allies have 59. Congress needs 44 seats to retain its majority.

Mr. Yadav, the Samajwadi leader, has pushed for the rights of farmers and the underclass and favors limiting the use of the English language in government. The party, based in India’s most populous state, Uttar Pradesh, is made up mainly of Muslims and farmers.

Representative Gary L. Ackerman, Democrat of New York, who arrived in New Delhi on Thursday, said he expected that Mr. Singh would arrive at the Group of 8 meeting with the deal in hand.

Mr. Ackerman, chairman of the House Subcommittee on the Middle East and South Asia, said in an interview that Indian officials had told him necessary approval of the agreement by the IAEA was “basically a done deal.”

Still, time is quickly running out for India’s divided political parties to come together, he said. The latest that the deal can be sealed is now, he said.

Asked if there is time to push the deal through the United States Congress before Mr. Bush leaves office, he said: “Possible? Yes. Probable? No.”

If the Indian government wins approval by international regulators by August, the United States Congress could vote on the deal soon thereafter, he said. The current Congress is lined up to vote favorably, he said, and he urged the Indian government to take advantage of the situation.

“I came here because we are hopeful,” he said, and the Indian government is “concerned.”

by NYTimes.