Obviously we have enemies. They just aren't a nation in themselves. This is what makes this war different from one where you can beat a geographical location, and sign surrender papers.

When a nation is actually on the terrorist's side, their police forces are no longer an option.

There are a number of countries that have either directly supported terrorist attacks on the U.S. and its interests, or have looked the other way while their territory is used for camps, or their resources are used to support terrorism. In the latter case, there is at least a chance of working up their internal security forces against the terrorists, but it's spotty at best. Witness Pakistan and Saudi Arabia.

In the former case, there is NO police solution, and something has to be done from outside.

In nations where the governments and police forces are hostile to terrorism, like Europe and many others, there has considerable police success against terrorists and cells actually located in those countries. Unfortunately, not all of them fall into that category.