  In this paper the standard prisoners' dilemma is embedded in environmental
conditions in which the interaction takes place. This provides a theoretical
background to the analysis of the empirical studies which indicate that
including additional factors when considering an alliance is very important. We
show that such an approach, though theoretically simple, provides a powerful
tool for suggesting successful strategies for forming, maintaining and
withstanding a rival attack on an alliance, projecting an alliance possible
success and determining which measures must be taken to maintain an alliance in
a changing environment. It also provides insight into the possibility of
preventing alliances in rivals. The relative simplicity of this framework means
that the approach can be easily applied when the real life decisions are taken.
