With the US committed to withdrawing all combat troops from Afghanistan by the end of 2014, its ability to use the Pakistan transit route had become essential. But the agreement did not come easily for either side, each suspicious of the other and mindful of domestic political pressures.
The White House initially resisted anything smacking of an apology, fearful of playing into Republican charges that President Barack Obama was failing to defend American interests, just as the 2012 election campaign moved towards its climax.
More fundamentally, many policymakers in Washington, pointing to the ties between elements of the Pakistani intelligence services and the Taleban, wonder aloud whether the country is a US ally at all.
Those doubts only intensified with the May 2011 US commando raid that killed Osama bin Laden, and the discovery that the al-Qaeda leader had been living for years in Abbottabad, just two hours' drive from Islamabad.
For Pakistan the same considerations apply, but in reverse. With anti-Americanism running high, the Pakistan Government could not do anything that could be construed as a concession to the US - especially after the bin Laden operation, seen as a humiliating violation of the country's sovereignty.
- Independent