The fallout from the shooting of 16 Afghan villagers by a renegade US soldier has highlighted the mistrust and exhaustion on both sides in a decade-long war increasingly seen as a lost cause.
In Afghanistan there have been angry words from President Hamid Karzai but as yet no widespread outpouring of rage on the streets as there was last month after copies of the Koran were burned at a US military base.
"Many Afghans think that American soldiers kill civilians all the time," said Kate Clark of the Afghanistan Analysts' Network.
"I've found it difficult to find Afghans who believe it was one American acting on his own, so this is maybe seen as just a more egregious example of their regular practice."
In the United States and among its major European allies, the massacre is likely to increase what opinion polls show to be widespread disenchantment with America's longest war and a desire to get the troops out as soon as possible.
While President Barack Obama warned this week against "a rush for the exits", he also said it was "important for us just to make sure that we are not in Afghanistan longer than we need to be".
US-led International Security Assistance Force (ISAF) combat troops are already due to pull out by a deadline of 2014, but the massacre may affect negotiations over a strategic treaty covering relations after that.
"Initially the Afghans had demanded as a condition of the talks that their courts should have jurisdiction over US forces in Afghanistan," said IHS Global Insight analyst James Brazier.
"Although the US would never countenance such an agreement, the latest illustration of why the Afghans desire such jurisdiction could conceivably bolster their other outstanding condition: to prohibit night raids conducted by ISAF forces, which Karzai blames for high civilian casualties."
The refusal by the United States to lift immunity for its troops scuppered attempts to broker a similar treaty in Iraq.
However, Karzai faces challenges after 2014 not only from Taliban insurgents but from tribal warlords who plunged the country into civil war in the early 1990s following the Soviet Union's pull-out after a 10-year occupation.
And while the United States may be keen to maintain a foothold in a country neighbouring Iran -- and to help prevent it from once again becoming a haven for Al-Qaeda -- it is likely to come down to a question of who needs who most.
A conflict that Western politicians termed a "good war" when they sent in troops to topple the hardline Taliban regime for sheltering Al-Qaeda leader Osama bin Laden after the 9/11 attacks, has gone sour.
Afghan soldiers being trained to take over security when the US and its NATO allies pull out are increasingly turning their weapons against Western troops.
Nearly one in five NATO soldiers killed this year has died at the hands of their supposed allies -- six of them Americans who were killed by Afghan colleagues after the Koran burning.
Signalling the deepening mistrust between the two sides, NATO countries pulled their advisers out of Afghan government ministries after two were shot dead by an Afghan colleague in the interior ministry.
But it is civilians, like the women and children the US soldier shot in their homes in his pre-dawn rampage on Sunday, who have borne the brunt of the war.
More Afghan civilians -- 3,021 -- were killed last year than the total number of US and allied troops who have died in more than 10 years -- 2,915, according to counts kept by the UN and icasualties.org.
Most died at the hands of Taliban insurgents, the United Nations says, many killed by bombs supposedly targeting the 130,000 US-led troops in the country.
There is grief and anger in the villages where Sunday's violence saw toddlers killed in their sleep or dying in a waking nightmare.
On Tuesday gunmen opened fire on an Afghan government delegation at a memorial service for the slain villagers, killing a soldier, but in a country that has been at war for three decades, more violence is not always seen as the answer.
Bakhtyar, a resident of Kandahar who uses one name, summed up his reaction to the US soldier's shooting spree: "This requires a political solution. If we demonstrated (the Taliban) would misuse it and turn it into violence.
"This time an American has killed Afghans -- we Afghans, too have killed Americans in the past."