Anyone who tries to tell you that their sense of morality originated entirely within themselves is either lying or was raised totally devoid of contact with other living beings.
That said, I personally define my own morals based on what I see in the world, what I think about it and what I feel about it. I don't believe either way in a "higher power" but I think the Bible has a few good points and that Jesus was a pretty stand-up guy. Question: Do I count as at least partially following a "higher source" even if I don't follow every last word? Your answer to this question will be quite illuminating.
First and foremost I ask myself what negative effects an activity, action, event, etc. will have on any and/or all people involved. Next I try to consider what kind of precedent it sets - how it'll affect the future and if that precedent will lead to future action that will exacerbate the effects of the current event in question.
Yes, although since I've never used that particular phrase I probably ought to use some caution in answering in the affirmative. What exactly do you mean by "situational ethics"?
It has since coming to this site.
As I learn more it grows and changes, as do my views on just about everything, so I suppose the answer is yes, it is effected by current events and politics (as much as it is effected by reading the works of authors recent, recently deceased, and long dead).