Moral Relativism / Absolutism

I suppose the opposite of moral relativism is moral
absolutism - some group, usually religious, telling us
exactly how we ought to think and live.  Christians
used to defend slavery and the disenfranchisement of
women on absolute moral grounds.  Most Christians
today read their bible differently.  Have the moral
absolutes changed?

We also live in a secular democracy.  The founding
fathers knew from close-up what happens when one
religious group imposes their view of the truth on the
broader society.  This is why we have constitutional
protections in place to separate church and state.
Whose religious laws govern us?  And when the
population shifts, and another religion is dominant,
do we change our laws?

As far as moral relativism, we have atheists defending
a Christian's right to pray in school, and Christian
clinic bombers.  Usually, the same Christians who decry
the decline of personal morality make no comment on global
injustice, grossly unfair business compensation and
profiteering, and endemic political corruption.  Is this
moral relativism?  Instead of sloganeering, we need to
find ways of engaging our community and elected leaders in
substantive discussions about justice, ethical
behavior and how to address issues, like genetic
engineering, that have come up after the world's moral
codes were written.