I gave up playing wargames many years ago when I found that they had to resort to artificial contrivances to attempt to simulate the elements of logistics, intelligence, convergence and sacrifice that dominate military success factors. A decade and a bit ago I tried a computer wargame ("V for Victory: Velikiye Luki"), but with perfect intelligence, I knew where the computer opponent's fixed supply lines were, so with some sacrifices to breakthrough the lines, I converged on these and before the end of the game all enemy units were eliminated. This would be an impossible outcome in the real situation.

In recent years one of the best writers on military related issues has been Martin Van Creveld. He has produced two landmark books, Transformation of War (1991) and Supplying War (1976, new issue 2004), the latter covering the mostly ignored but crucial issue of logistics. For well-thought-out discussion on these writings, see this:

The Van Creveld Factor

Here are two fascinating sets of insights by Van Creveld, with the warning that he can be a "controversialist" as the above referenced discussion notes.

Interview with Van Creveld

As history since Hiroshima shows, the best, perhaps the only, way to curb war is to deter it with such overwhelming force as to turn it from a struggle into suicide. The best way to mitigate it is to use all possible means to bring it to a speedy end. I think both Clausewitz and Sun Tzu would agree on these points.

Then in a masterpiece article covering all the key elements, Van Creveld nails it:

Why Iraq Will End as Vietnam Did

In international life, an armed force that keeps beating down on a weaker opponent will be seen as committing a series of crimes; therefore it will end up by losing the support of its allies, its own people, and its own troops. Depending on the quality of the forces - whether they are draftees or professionals, the effectiveness of the propaganda machine, the nature of the political process, and so on - things may happen quickly or take a long time to mature. However, the outcome is always the same. He (or she) who does not understand this does not understand anything about war; or, indeed, human nature.

Wargames show the direct military outcome, but they do not show the longer term human one.