It is internal as
>well as external.

>
>If we can agree that action is a key to power, having the
>ability or freedom to make something happen, then maybe we
>can also agree that some people have access to this key more
>than others? Why do some people--given equal resources and
>opportunities--overcome and succeed and others just give up?

It might be related to the characteristics of an individual. Some might not give up on their own wishes, but forced to.
If we say a teacher has the power to influence his/her students that can be based on dedication, performances, open-mindness and such. If one individual has the power in herself/himself to act to change things, in that arena the enemy is the compromise. If an individual believes that ideology itself can change and affect people, and that person is kicked out of the system....is that person just giving up or becomes a victim?

I think the system or the environment in which the individual works and acts, it is probably the most important factor. Those outside scenarios can be a party, an organization, a community group etc. the system can work towards the individual or not. so i guess what i am saying is that the system can allow/not allow the individual to exercise his/her power.