Really it boils down to retaining or losing the power of majority...
Group A supports an issue like banning green apples, they are green, we hate them, they must be banned.
Group B supports the diversity of apples, green, red, yellow, they are all equal we will not ban them.
Well the voters like all apples, who supports all apples, group B does, lets vote in all group B members, since the group A members will not let us have green apples.
Years go by...
Well now it is time to elect the new groups, well Group A sees the error of its ways, "apples were a hot topic, but they "burned us" so we will stay away from that issue".
A new hot issue has come along, and the voters really agree the new hot issue is really bad and it's all group B's fault. So Group A supports the fact that the hot issue is bad too.
The voters see this and vote in a majority of Group A members because they all agree, it's bad, group B really screwed up, they have to go.
Next time around, group B will see the error of their ways and so forth...