Another issue is attacking American citizens fighting for the enemy. Again, this has happened many times before in wartime, including irregular operations. In the past, the enemy was the enemy and being a traitor in addition to being part of the hostile force did not make any difference. What it really comes down to is a philosophical attitude towards dealing with terrorism. On one side you have those who believe it should be just a police matter, while others believe military forces should help to eliminate this threat.
But this is mostly about ROE (Rules Of Engagement) and demands for fewer civilian casualties, even if it means the troops are put in more danger. Sometimes this approach actually puts civilians in more danger. For example, in the last few years American troops have increasingly encountered angry Afghan civilians who demand that the Americans act more decisively in pursuing and killing Taliban gunman, even if it puts Afghan civilians at risk. This is an unexpected side effect of a change, four years ago, of the U.S. ROE in Afghanistan. This was in response to popular (or at least media) anger at civilians killed by American smart bombs. As a result of the new ROE, it became much more difficult to get permission to drop a smart bomb when there might be civilians nearby. Now American commanders have to decide who they should respond to, Afghan civilians asking for relief from Taliban oppression or Taliban influenced media condemning the U.S. for any Afghan civilians killed, or thought to be killed, by American firepower. What to do?
Taliban propaganda, and the enthusiasm of the media for jumping on real, or imagined, civilian deaths caused by foreign troops, made people forget that far more civilians (about four times as many) had been killed by the Taliban. But because Afghans have been conditioned to expect more civilized behavior from the foreign troops, much less media attention is paid to the civilians killed by the Taliban and al Qaeda.
Of course Afghan civilians are aware of who is killing most of the civilians, and that's why the Taliban and al Qaeda get low numbers in local opinion polls. But the media, hammering foreign troops every time they kill a civilian or are simply (often falsely) accused of doing so, led to the ROE becoming far more strict than it ever was in Iraq. Thus, one Taliban victory you don't hear much about is how they turned their use of human shields into a powerful, and very successful, propaganda weapon against NATO and U.S. troops and an excellent way to avoid getting attacked.
Under the new ROE you had to, in effect, do a casualty analysis and consult a lawyer before a deliberate missile or smart bomb attack is made on the Taliban. To their credit, the U.S. Air Force targeting specialists (who do most of this) can carry out the analysis quickly (often within minutes). Even the lawyers have gotten quick at the decision making game. The bad news is that attacks are often called off just because there's some small risk of harming civilians.
The Taliban are aware of the ROE and take advantage of it. The Taliban try to live among civilians as much as possible. But the Taliban and al Qaeda do have to move around, and the ability of NATO and U.S. ground forces, aircraft, and UAVs to keep eyes on a Taliban leader for weeks at a time has led to the deaths of many smug guys who thought they had beat the system.
The U.S. Air Force has managed to reduce civilian casualties, from deliberate air attack, to near zero. Most of the Afghan civilian casualties occur when airpower is called in to help NATO and U.S. troops under attack. In these conditions the ROE is much more flexible but now Taliban use of civilians as human shields can sometimes be allowed to get friendly troops killed. The tactics used by foreign troops will change to adapt to this and there may be tense situations where Afghan troops are getting hammered, calling for a smart bomb, and told that they can't have it because of the risk of civilian casualties. Another risk is the possibility of the Taliban dragging some women and kids along with them when they move, simply to exploit the ROE and avoid getting hit with a smart bomb.
The new restrictions on the use of air power, and the greater Taliban use of civilians as human shields, has enabled the Taliban to avoid a lot of situations where they would otherwise get killed. When they are out in the open, the Taliban still get toasted regularly by foreign troops (with or without the use of smart bombs). The new ROE is based on the fact that the Taliban are increasingly openly hated by Afghan civilians. This has led to more tribes getting angry enough to fight the Taliban. This is why outside of Pushtun areas (most of southern Afghanistan) you see very few Taliban. The Taliban are basically a Pushtun thing and non-Pushtun people are violently opposed to any Taliban moving into their territory. The new American ROE is hoping to exploit that growing hatred of the Taliban in the south. But in some areas of the south, particularly Helmand province (where most of the world’s heroin comes from), where the Taliban and locals are in the drug business together, there are still fans of the Taliban. Moreover, the Taliban recruits heavily in Helmand and adjacent provinces. This is where the Taliban came from (initially as refugees living in Pakistan). Helmand has always been ground zero in the fight against the Taliban, and now the fight has gotten harder and more dangerous.
Afghanistan also made it clear that you often have terrorist situations that only military type operations can deal with. Police are not much use in a war zone.