For every action, there is an equal and opposite reaction.

In politics, when one Party attempts to hammer the other, there is going to be an equal and opposite reaction.

If we try to force our viewpoints on someone, they will react negatively.

It is a theory of Sir Isaac Newton. It is as much a law of human nature, as it is science, in my opinion.

It is something we should bear in mind when we try to communicate with those who disagree with us.