(CNN)After more than a decade of foreign intervention in Afghanistan, was it all worth it?
We invited you to pose questions like these on Facebook to our correspondent Nick Paton Walsh, who just returned from a reporting trip in Afghanistan.
While he was there, he witnessed a chilling development: ISIS training in the mountains, recruiting disillusioned Taliban fighters.
Paton Walsh spoke to a woman who endured a hideous ordeal. After getting raped by her cousin's husband, then being jailed for adultery, she was forced to marry her attacker.
And he spent time with the remaining U.S. troops in the country's troubled east, who are struggling to prop up a crumbling and corrupt Afghan army.
Here's what you, the readers, asked him on Facebook.
What exactly was the U.S. mission in Afghanistan?
The mission has varied since the beginning, says Paton Walsh.
"At first it was kill Bin Laden and dismantle AQ (Al Qaeda), and depose the Taliban. But then it became 'Fix Afghanistan.' And then, now, it is leave Afghanistan with an army that can cope. And is slowly losing those last 6 words of the last sentence."
How does ISIS in Afghanistan affect the U.S. strategy there?
Nick Paton Walsh says: "It might in the end slow their drawdown, particularly if ISIS develop the military capability they are now not showing readily. The Obama administration is very keen to have all troops in the Embassy by 2017, but his successor might alter that."
Has the U.S. done lasting good in Afghanistan, and should it still be there?
Paton Walsh says he's not sure.
"(The U.S. military) has spent a lot of money, and made some people rich, leaving behind a lot of infrastructure that was not there before. They have -- in their eyes -- killed many insurgents.
"But if you are asking why and if a longer term broader military presence is needed? I am not sure it is. The 100,000+ (U.S. troops) that instilled some patchy sense of security isn't sustainable.
"The Afghan army eventually have to come to an accommodation with the insurgency, and a form of political deal has to be struck."
Has the U.S. intervention in Afghanistan contributed to the rise of ISIS?
Paton Walsh says, "Probably not, ideologically. The insurgency in Afghanistan may have 'loaned' some fighters who ended up in ISIS ranks, but in the end (the conflict in Afghanistan) is distant and quite distinctly not Arab."
Still, Paton Walsh notes Afghanistan has been a training ground for extremists seeking skills, like bomb making.
"Afghanistan may end up again being an incubator or haven for extremist militants, but it is not much of a lightning rod in the broader chaos of the Middle East now."
Is the Taliban evolving to become part of ISIS?
Doesn't seem to be the case.
"The Taliban are resisting pretty clearly," says Paton Walsh.
"ISIS, if they do emerge, will be a parallel often competing system to the Taliban, but they face a few challenges in Afghanistan, not least decades old networks of loyalty, cash and guns."
What is being done to protect Afghan women from violence?
Despite some new laws, not very much, says Paton Walsh.
"There was the Law on Elimination of Violence Against Women, which was a bid to enshrine those values in legislation, but given the Afghan government's struggles to defend its population from the insurgency in general, womens rights have taken a back seat."
Could protests help women in Afghanistan?
A reader mentioned many Afghan women have been protesting after a woman was beaten and set ablaze for allegedly burning the Quran last month. Could these demonstrations be a turning point for women's rights in the country?
Paton Walsh says the protests "looked like a refreshing popular movement for change... but have not sparked a sea change. That will take a lot more."
Does the U.S. have a plan for Yemen?
While the Q&A was about Afghanistan, some readers were curious about developments in Yemen.
Paton Walsh weighs in: "I am not sure a (U.S.) plan as such has formed for Yemen. Things are moving too fast there now."
Could ISIS take over large parts of Yemen?
One reader asked if ISIS might be able to exploit the chaos in Yemen to seize territory, as it did in Syria during the civil war there.
Paton Walsh says it doesn't look likely, for now.
"ISIS have claimed a bombing. They remain limited and a competitor to AQAP (Al Qaeda in the Arabian Peninsula). And then there are the other 7-8 actors in the Yemeni war who will have say if they turn up. It's not going to be easy for (ISIS) there."
What's the most important lesson you've learned?
"Always pack a towel and don't drink tap water, anywhere," says Paton Walsh.