The opposition isn't partisan. http://reason.com/blog/2017/08/22/anti-interventionists-in-congress-respon
No easy answer sport. Not so worried about NK or ISIS but the destabilization of Pakistan (they have nukes) and the human tragedy in the region will be an issue. To be balanced is; does what we get from being there justify the lives and trillions of dollars wasted so far and the exponentially greater cost as time passes? How does that balance with the cost of leaving. I don't know but we are leaving our life force in the sands of Afghanistan and Iraq.
We have been spilling our blood there for 17 years and that's about 15 too many. Either obliterate them or get out.
Not a good option. We are not at war with the nation of Afghanistan. Where would we drop them? On top of every mountaintop where there might be some caves hiding the Taliban? If there's anything at all we should have learned from the Russians it's that you can't win a war in Afghanistan.