But nor were the Tamil Tigers, under their leader Velupillai Prabhakaran, any more trusting.
The former head of the Sri Lankan military was widely credited with the 2009 victory over the Tamil Tigers.
In fact, Sri Lanka's Tamil Tigers rebel group was among the first in the world to deploy suicide bombers.
Mr Wickremesinghe saw a surge in his Tamil support, after he had advocated foreign-aided talks with the Tamil Tigers.
Sri Lanka's army did the same after defeating the Tamil Tigers in 2009.
Many ordinary Sri Lankans remain suspicious both of his liberal economic policies and of his policy towards the Tamil Tigers.
Although the Tamil Tigers are unquestionably on the back foot, it would be dangerous to discount them as a spent force.
The island state has witnessed a violent insurgency for 25 years by the Tamil Tigers, a largely Hindu minority amid a mostly Buddhist Sinhalese majority.
Police in northern Sri Lanka have made a series of arrests which they say are linked to combating terrorism, three years after the separatist Tamil Tigers were defeated.
BBC: Sri Lanka arrests: Jaffna police detain 'terror' suspects
But Western diplomats say a strong statement of concern has been sent from New York which will be closely followed by both the Tamil Tigers and Sri Lanka's government.
In May 2009, Sri Lankan troops mounted a massive campaign to end the war against the Liberation Tigers of Tamil Eelam, a separatist group better known as the Tamil Tigers.
And the post-11 September international mood against terrorism has also brought new pressures on the Tamil Tigers to end their violent struggle that has bled the country for more than 20 years.
For most of the past decade, with neither the Sri Lankan army nor the Tamil Tigers looking strong enough to triumph on the battlefield, it made sense for India to remain aloof.
Ms Pillay, a South African of Tamil extraction, had outraged the Sri Lankan government by calling for an independent investigation of alleged atrocities and war crimes by both sides in the war against the Tamil Tigers.
ECONOMIST: A long-despised watchdog wakes up, barks and even bites
On Wednesday the UN Security Council, which had been accused of inaction, called on the Tamil Tigers to lay down their arms and urged the Sri Lankan government to allow international aid agencies into areas of need.
Sri Lanka's government denies the accusations of rights groups, saying on Thursday that fewer than 8, 000 people were killed in the final months of the 26-year war, and arguing that it deserves more credit for putting thousands of former Tamil Tigers through a rehabilitation process.
Heavy fighting erupted in eastern Sri Lanka between government troops and rebels from the Liberation Tigers of Tamil Eelam.
The result looks unlikely to advance a settlement of Sri Lanka's 17-year war against the Liberation Tigers of Tamil Eelam, who want a separate state in the north-east for the Tamil minority.
War there has been waged between the Sri Lankan government, tending to represent the interests of Sri Lanka's majority, and predominately Buddhist, Sinhalese ethnic group, and the Liberation Tigers of Tamil Eelam, who claim to represent the mostly Hindu Tamil minority.
Neutral observers say the Tigers have also shelled Tamil civilians during their offensives, as has the Sri Lankan army.
Two of her new-found allies are Tamil parties that have distanced themselves from the Tigers.
As for the Tamil minority, thwarted of the independent homeland for which the Tigers had been fighting, it was, at just 12% of the 21m population, too small to sway an election.
Sri Lanka's military is on a major offensive to try to crush the Tigers and end their fight for an independent state for the ethnic Tamil minority.
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