More generally "net" means a summary or a very simple statement of the core point.

In writing to be understood, often it is good be clear, and even too simple, about the main 'points'. Otherwise it is too easy that no 'points' at all get across.

Your comment and at least two 'siblings' are far more thoughtful than mine was so that my oversimplifying with "net" is not appropriate.

Back here in the US, after 9/11 and now 12 years in Afghanistan, we need to make some difficult decisions: We tried, hard but in total ('net'!) not hard enough, to make Afghanistan a "shining city on a hill" but apparently have failed and maybe even 'net' have done more harm than good.

Bin laden is gone. The Taliban government that let Bin Laden use their country as a base to attack the US is not gone but is out of power. There are stories that some even in the Taliban now understand that it was a big mistake to let Bin Laden use Afghanistan as a base to attack the US.

The US has tried 'nation building' in several countries of the world. We were largely successful in Germany and Japan. With US military protection, Taiwan and South Korea have done well. The US has tried hard to have peace with both Russia and China and not have them become another 'Axis' like Germany and Japan in the 1940s. Still, in Viet Nam, Cambodia, Iraq, and Afghanistan, the results of US efforts been from frustrating and/or poor (Iraq) down to worse.

Viet Nam is the grand tragedy: I have a nice 600 dot per inch black and white printer from Brother, made in Viet Nam. Terrific for Viet Nam. The US couldn't be happier. The Brother printer is much better than the HP printer I bought in 1994. That Brother and Viet Nam are at least in part beating HP in the printer business is mostly fine in the US (except for HP stockholders!). As far as I can tell, what Viet Nam is now is just fine with the US. The big, huge point for the US is that Viet Nam is not part of some Axis of Moscow, Peking, and Hanoi that seemed to be a threat starting just after WWII where the US had just defeated the Axis and didn't like things that looked like an Axis. The WWII Axis also hurt Viet Nam -- Japan occupied Viet Nam.

But, the way Viet Nam is today, it is clearly no threat to its neighbors or the US, and that's really all the US wanted. The US didn't want a colony, and for the rubber or lumber, wanted to pay fair prices for it.

The tragedy is that Viet Nam and US relations as they are today could have been just the same in the early 1970s, the 1960s, ..., back to just after WWII (to heck with the French) just by both sides just deciding to and shaking hands on it.

In summary ('net'), the US has tried, sometimes at great expense in US blood and treasure, often with much more expense in blood in the other country, sometimes been successful, and sometimes not. When we have failed, we didn't really know why.

For why the US was successful in Germany and Japan, both countries had very strong, highly disciplined cultures, suffered just devastating, horrible, defeats, with homeless people wandering cold and hungry in the streets with rotting bodies under piles of rubble, and then used their discipline to say "never again", mean it, implement it, do a lot of really hard work, and rebuild themselves.

So, 'culture' played a part. So, why not success in Afghanistan? My view: Culture. The culture was different; either the US didn't understand it or it was insufficient. What was that culture? In a word, Islam; it runs nearly everything. The US tried to build a 'secular' (independent of religion) democracy, and the Taliban have Islam on their side. The US has B-52 bombers from 40,000 feet, GPS location, A-10 airplanes that reduce tanks to piles of scrap iron in seconds, supersonic F-16 airplanes that can reduce a tank to scattered scrap iron in even less time, schools, hospitals, etc. and lose, and the Taliban have sticks, stones, some RPGs, and rusty AK-47s and win. To me, the main difference is that the Taliban have the 'culture', in this case, Islam, on their side.

Whatever, likely the US will be leaving Afghanistan, fairly soon.

For the US, it's much more difficult to attack us now. In particular, it's difficult even to have nail clippers on a US commercial airplane. And I can believe that in many Islamic countries, anyone shouting "Jihad! Death to ..." will quickly get a 'corrective lesson' they won't forget, maybe even can't forget.

For Turkey, if they become more fundamentally Islamic, then they will find that the US, NATO, the EU, and maybe even Russia will become much less friendly.