For global geopolitics, one of the biggest changes brought about by the withdrawal of the U.S. military from Afghanistan is that the U.S. has also withdrawn from the world's heartlands. What the U.S. will do next is what a maritime nation would do, i.e. exerting its influence through power projections in key regions which will be concentrated around the Atlantic and Pacific routes. The most crucial impact of the U.S. military withdrawal from Afghanistan is that, the U.S. has completely turned into a maritime power, while China has completely turned into a land power.

As Taiwan is on the Pacific route, the U.S. will definitely intervene in it. It is no longer a priority for China to engage in the Maritime Silk Road, like its projects in Sri Lanka. China's focus instead will be on cooperation in land rights. It should also manage its relations with other nations in the world's heartlands, including Iran and Germany, but most importantly with Russia. While China will face numerous problems in this, it will still have to adopt such measures as it has missed out its window period.

Meanwhile, as Japan, South Korea, and North Korea are located at maritime region, China will have little influence over them. As for Vietnam, as it is located on the Pacific route, in the next 10 years at most, the relationship between China and Vietnam will undergo drastic changes. China might also aim to control the South Sea, though the actual possibility for its navy to intervene in other places is very slim.

To determine the outcome of the possibilities mentioned here, there should be an observation period of ten years. By then, we will be able to see which possibilities have indeed occurred.

Final conclusion and policy recommendation:

The most crucial impact of the U.S. military withdrawal from Afghanistan is that, the U.S. has completely turned into a maritime power, while China has completely turned into a land power.