> In particular, why would crowdsourcing a foreign policy agreement be a good idea?
I think Internet's collective intelligence could be higher than that of any person on a well defined task.
> Would you crowdsource the plan for your open heart surgery?
Desperate situations, call for desperate measures. If I did, I would ask for "qualified heart surgeons to contribute" the same way I asked about "people with the understanding of geopolitical situation".
There are people that are not in the political administrations of the warring sides that have called the situation much more correctly than the administration. Example: https://www.youtube.com/watch?v=JrMiSQAGOS4