Pakistan won't let Afghanistan settle down if it has anything to say about that. The Afghan government would like to settle down even if Iran is the path out of Pakistan's stranglehold.
Iran and Afghanistan are close to completing negotiations for a comprehensive strategic cooperation agreement that will officially give Afghanistan a new economic and military ally against the Taliban and the Pakistani military. The last item being negotiated is the security aspects. Apparently, this item is not a roadblock but is subject to a fair amount of haggling. One item to work out is the need for Afghanistan to continue working with the United States against international terrorist groups, like al Qaeda and ISIL, that still maintain a presence in Afghanistan.
I've long worried that Pakistan controlled the major line of supply into Afghanistan. How I slept during our surges in that landlocked country still astounds me. The Pakistanis knew there were limits to how much America could push them.
One of the benefits of overthrowing the mullah regime in Iran and replacing it with a government that reflects the pro-American sentiment of the people of Iran will be the land corridor it will open to Afghanistan.
Now, our access to Afghanistan is from the north through the unstable "Stans" and back through an increasingly unfriendly Russia; or through Pakistan which we have to coddle to keep land-locked Afghanistan from being cut off from us.
Open up a supply route through Iran to Afghanistan and suddenly we don't need to be quite so reliant on our Central Asian bases or so careful with a Pakistan that will not crack down on the Taliban who hide and organize inside Pakistan. We won't have to be so shy when it comes to hunting bin Laden there, either.
Will this be helpful with mullah-run Iran in control of the lines of supply? At least India will have a role in the supply route, if the earlier news is still accurate. I imagine it is simply based on the financial angle.
But we'll see if Afghanistan can play one devil off against another to finally achieve a lower level of endemic violence. It's always possible that these two predators will simply come to an agreement on spheres of influence where they are free to be devils.