I've let a few of you guys weigh in here... now I'll give my opinion, with some personal insight.
I agree we need to get out of Afghanistan. Going in, in October 2001 was the right thing to do, I'm sure we all agree. The mission of denying the Taliban backed Al Qaeda a safe place to operate and killing Osuma Bin Laden. These two key mission objectives have morphed into rebuilding a nation based on democracy in an extremely non-democratic society.
We have dumped billions of dollars into infrastructure and building a military to attempt to keep the democracy in place through security and winning the people over(hearts & minds). The problem is the people in that country do not want the same kind of government we have. So, once we leave the U.S. trained Afghan military & police will either drop what their doing or be defeated by the stronger and better trained(for their own countries landscape) Taliban. Vietnam anyone?
We have done what we can do without bringing our own country down. The saying "give until it hurts" comes to mind. It's been hurting for a few years now. Going to, and continuing a war for nation-building is a terrible idea... that will end with thousands of people dead and the "building" nation bankrupt.
Now, my insight comes from 1. I spent 7 months in the Hindu Kush mountains near the Pakistan border... I saw, smelled, heard, communicated with, and learned about the local population. Along with learning what combat is like with a well trained, knowledgable, small, fast moving, and determained enemy defending his land... in his part of the world. And 2. I'm not ignorant so I educate myself about as much as I can, when I can.
We are the most powerful military force in the world, no doubt. Our weakness ultimately stems from our lack of "heart" in this conflict overall. Yes, many Americans believe in this mission down to their bones. And yes, in those moments of "you" or "him"... you'll fight like you never thought you could. But it's not enough to win absolute victory in the end.
Then we have the issue of this war contributing to our economic collapse... it is. Aint no moving around that one. When the dollar collapses, everything collapses.... everywhere. The third world nations will remain so, the thrid world nations under cover will fall back to pure poverty and tyranny. And the first world nations will revert into third world... it will happen.
In the end, leaving under perceived failure won't sting so much if it helps preserve our nation.