One of the things that came up in discussions about the NATO supply routes reopening in return for a US apology on Salala was trust, or lack thereof, between the US and Pakistan. I think trust is definitely important but I also think it’s a bit overrated as a factor in this context.
Trust matters most in those situations where two (or more) parties are leaving the possibility of mutual gains on the table because of a lack of trust. That is, we live either in a Prisoner’s Dilemma world or a Stag Hunt world or something similar. Presumably, if the parties believed that the other would do the right thing in the future – i.e. had trust in the other – they too would do the right thing, thereby realizing the mutual gains. Importantly, in these worlds, the parties are actually better off if they cooperate.
I’m not sure, however, that these worlds really reflect the US-Pakistan case. I think the better analogy would be Deadlock, where the parties simply want different things. In this situation, trust has no role to play whatsoever. It cannot help in ensuring cooperation because the parties’ goals are incompatible.
On everything from the ethnic makeup of the post-2014 Afghan government to Pakistan’s role in a post-2014 Afghanistan to opinions and policies toward China to opinions and policies towards India, the US and Pakistan have irreconcilable differences. Under these circumstances, we could live in a world where the US and Pakistan trust each other with absolute certainty and yet still not reach cooperative outcomes. The existence of trust cannot make them want different things.
Put differently, the fracturing of the US-Pakistan alliance is not a puzzle at all and should not be thought of as such. There was a time when cooperation was easier, because goals overlapped to a considerably greater degree (al-Qaeda, mainly). That is no longer the case. In fact, one could make the argument that there is no stronger indication of al-Qaeda’s relatively crippled state than the breakdown in US-Pakistan ties. Just like the Cold War, which could only be born once Nazi Germany died.