President Trump's stated goal during his August 21 speech in Arlington, Virginia was "winning in Afghanistan". The unfortunate fact is that between US and Middle East realities, "winning in Afghanistan" is highly unlikely--probably impossible.
Part of the problem is the extraordinarily complicated nature of Afghanistan and the Middle East region that has existed for centuries, complications that have been exacerbated in recent times. In the past two centuries, England, the Soviet Union and the USA have all invaded Afghanistan, yet none of those invasions has been a "winner".
If we start with an examination of the physical characteristics of the region itself, it will immediately become apparent that the years of colonial rule did nothing to help today's situation. In the late 19th and early 20th centuries, European colonial powers drew and redrew national boundaries in ways that were in their own interests and for their own profit, but had no connection with demographic realities. A fine example of this is the Durand line of 1893, established by the British, which created the boundary between Afghanistan and Pakistan, but divided a homogeneous Pashtun people into two groups in two countries.
The DNA of the region is based on tribalism, ethnicity and sectarianism. Those three things are the primary causes of most of the frictions that exist both within and between the countries of the region. The fragmented nature of these countries, Afghanistan most emphatically included, where primary allegiance is to some grouping below the Nation level, makes and national primacy difficult to impossible to achieve. National cohesion does not exist sufficiently within national boundaries to permit the establishment of nation-wide democratic governments, encouraging the implementation of repression as the only feasible route to stability.
The Afghan constitution lists 14 separate ethnic groups and there are probably another six that are too small to be included. Ethnic Pashtuns alone divide into roughly 400 sub-tribes. Those sub-tribes can be co-operative, competitive, or confrontational, depending on the situation.
And then we have the sectarian issue. Sunni Muslims comprise about 90% of the population of 30 million. Shia Muslims make up most of the remaining 10% with smatterings of another 6-8 religious groups. These two branches of Islam are always at odds and often in conflict.
In addition, there is the two-edged sword of the Quran, the Hadith and the...