Finance minister P Chidambaram on Wednesday said that the DMK was aware of government's position on UNHRC resolution on Sri Lanka but changed its mind between night of March 18 and morning of March 19.
DMK chief M Karunanidhi threw the UPA government into disarray on Tuesday by pulling support for the ruling coalition over its "unwillingness" to take on Sri Lanka over alleged war crimes against minority Tamils.
The decision by the 88-year-old DMK supremo, whose party has 18 members in the Lok Sabha, leaves the UPA dependent on two mercurial allies for its survival: the Bahujan Samaj Party's Mayawati and Samajwadi Party leader Mulayam Singh Yadav.
Initial indications were that the two northern parties, who support the government from the outside, would continue to play ball, largely for their own compulsions.
But the UPA faces the prospect of a rocky year until elections in 2014, with key economic reforms likely to be relegated to the back burner.
Most vulnerable are contentious bills to open up insurance and pensions sectors, tax reforms and the privatisation programme.
If the BSP and SP stay put — possibly for their pound of flesh — the Congress-led grouping will have the support of 53 lawmakers from the outside. Added to a strength of 229, it would give the combine 282 seats, keeping its head above the 270 majority mark.
Working to the UPA's advantage is the lack of preparedness of most parties to face the electorate now, a reluctance that saved it when West Bengal chief minister Mamata Bannerjee withdrew the Trinamool Congress' support to the government in September.
"Since it would be a big harm to the Tamil race if DMK continues in the Centre when a situation has been created to the detriment of Eelam Tamils, DMK has decided to immediately pull out of the Union ministry and UPA," Karunanidhi, a one-time movie scriptwriter, said in Chennai.
He also ruled out outside support.
Karunanidhi's family is strongly entrenched in state politics, even if it has lost some ground after a drubbing in assembly polls in 2011, and getting on the wrong side of the party would leave few options for the Congress in Tamil Nadu: current CM Jayalalithaa is sympathetic to the BJP.
Even as it met the President to formally withdraw support late Tuesday, the DMK left a window open: Karunanidhi said he would reconsider his party's decision if India worked to strengthen a US-backed resolution at the United Nations Human Rights Council on Sri Lanka and the government brings a resolution in Parliament before March 21, urging the island neighbour to act on complaints of human rights abuses.
But the DMK's insistence that the terms 'genocide' and 'war crimes' be included in both the UN and Parliament resolutions made the task of Congress intermediaries very tough, and they were said to be trying to convince the DMK that these words could be used only after an international probe.
Karunanidhi wants such a probe, to look into alleged war crimes by the Sri Lankan army during their decimation of the Tamil Tigers in 2009.
Also, India cannot afford to set such a precedent as it opens the door to others to use the same weapon against it, say over Kashmir or the Northeast.
A government official said the administration was fine with the current draft because it reflected India's stated position on human rights and the principle of respecting national sovereignty.
Any further course of action — such as asking the United States to rework the resolution or proposing an amendment — would depend on direction from the political leadership.
"The latest draft of the US resolution on Sri Lanka may be acceptable to most countries and even Sri Lanka may be able to swallow it, but it pushes DMK to the wall further," acknowledged the official.
India's permanent representative at the UN in Geneva, Dilip Sinha, was set to arrive in Delhi late Tuesday for a final round of consultations.
Of the five DMK ministers, MK Alagiri — one of Karunanidhi's sons — is of cabinet rank. In addition to its 18 Lok Sabha MPs, the party has six lawmakers in the Rajya Sabha.
Chidambaram, who comes from Tamil Nadu, sought to mollify Karunanidhi, saying his "statement deserves all respect". Parliamentary affairs minister Kamal Nath said the process of consultation was on.
Karunanidhi's daughter Kanimozhi, an MP, said: "The DMK expected the Indian government to support this resolution and take it forward but, unfortunately, it did not happen. The final resolution has come and nothing of what was expected is there in it. So I think the DMK had no choice but to decide to pull out."
The DMK chief's archrival, CM J Jayalalithaa, was scathing in her criticism.
"The plan of Karunanidhi will not succeed and the people of Tamil Nadu will teach him a lesson. The people are fed up with such dramas enacted by Karunanidhi," she said.
The DMK convened an emergency meeting of the executive council, the policy-making body of the party, next Monday.