Selfishness.
All people are selfish. All people can be trusted to do whatever they think is in their own best self-interest 100% of the time. Republican, Democrat, Libertarian, Social Democrat, Communist, whatever.
Some people sense themselves as a part of a larger group, connected to the whole and realize that their well-being depends upon the well-being of those around them.
And some people regard themselves as the sole and only important beings. Those people give "selfish" a dirty name.
Arf