Social inertia is a term that applies the concept of inertia to psychology and sociology. It is used to describe the resistance to change presented by societies or social groups, usually due to habit. An example of social inertia can be noticed in United States inconformity with the SI standard units (see metric system in the United States for details.)
It is often observed in politics, when people consistently vote for one candidate or party out of habit, regardless of whether or not they actually would benefit from that vote.
One of the best examples of this is presented in the film The Fire Within.