Paul W. answered 12/06/19
Dedicated to Achieving Student Success in History, Government, Culture
A fundamental problem is contained, presumably unintentionally, within this question. The 'War on Terror' may be shorthand for the 'War on Terrorism', but in either case it refers to an illogical proposition. 'Terrorism' is a method of violent conflict. War is a state of violent conflict between groups of human beings, whether they be sovereign nation-states or non-state actors.
A 'war' cannot be waged against a way one or more people do something. Granted, actions can be taken to potentially prevent or discourage one or more people from doing something. These actions can be taken by one or more government's different agencies, military, civilian, or a combination of both. But these actions are more along the lines of law enforcement, just as acts of terrorism are closer in nature to criminal activity than military activity.
Can, for example, the United States Government conduct a war against a nation-state, a non-state actor, or some combination of the two that happen to employ terrorism? Certainly. But this would be a war, not against the method of violent conflict known as terrorism, it would be a war against a specific group of human beings.
No power on planet earth can completely stop individuals or groups of people from choosing to commit acts of terrorism because that would require some form of near absolute control over ever single human being on the planet. In this respect, a 'War on Terror' does not have a foreseeable ending.
The appropriate question is 'Can, for example, the United States prevail over groups of human beings, be they nation-states or non-state actors, who happen to employ terrorism?' The answer to this is, yes, this is certainly possible, but it certainly is not easy. Moreover, it would require a comprehensive international effort in which the United States would cooperate as a partner with nation-states around the globe.
How are we doing so far? At this point in time, I would give the United States a 'C'. On the one hand, organizations such as Al Qaeda and Isis have been severely degraded due to the efforts of the United States in cooperation with a wide variety of other nation-states. However, the current administration's approach of unilateralism in foreign affairs has weakened the connections with other nations that are indispensable for the international cooperation necessary to combat the groups that employ terrorism. Hopefully, future administrations will return to the post-World War II approach to foreign affairs practiced by the United States in which international organizations that bolster peace and stability in the world are given the support and guidance they need.