<span>"Externality" is the term which is used to describe an unintended side effect that affects a third party that had no involvement in the activity that caused the side effect. The side effect is called a positive externality if it benefits the third party, while it is called a negative externality if it is harmful to the third party.</span>
The Allies invaded the Mediterranean because they wanted to remove Italy from axis powers. Axis powers are nations that fought in the WW2 so they basically didn't want Italy to fight in the war.
Adolf Hitler´s goal was to defeat and conquer the Soviet Union in order to incorporate its vast territory into his planned empire, securing "Lebensraum" or living space, for the glorious domination of the German race, the superior race according to Nazi propaganda.
