Debacle, yes. Leaving them alone? Not sure. Several ways it could go in my opinion. Could be a lot of infighting, not allowing a government to get established. Could be that they follow whoever the leader is now. Or some other version. I fully expect that we haven't heard the last of that country, and it won't be too long before they start up some sort of trouble with a different country. Also expect despite what has been said by the President, I fully expect we, or someone, will have to return to Afghanistan, and that will return will be very costly.