Lets say we have two parties, X and Y, with two different solutions to a problem. The solutions also have negative side effects.
Here is a picture of the situation: (follow the link to left to a Southbeach Quickguide for more information about Southbeach modeller and how to interprete the model/images)
If we now consider how party Y might argue to gain followers or voters. They have lots of possibilities and can act on almost any of the items in the previous picture:
The blue boxes contains what the Party Y might say to win. And with Party Y perspective the various effects (arrows) now are of different "strengths".
It can be very beneficial to illustrate a situation with a map. And then consider what might happen to or how to act upon each item in the map. With the knowledge gained you can build a strategy and plan to execute. Or solve the problem you have.
And as you can see there are plenty of blue boxes that Party Y could use to form their strategy!
Use a map to find'em all!