Acceptable Discrimination?

Acceptable Discrimination?

I keep asking this basic question and so far I don't recall a serious answer if any answer at all.

Right ( "up in" ~;-) ) now, we are all about trying to get something passed to prevent discrimination based on X.

My question is:

What things are acceptable for a government to discriminate against its people for?

Is the list of things that are acceptable to use as a basis for discrimination so long that we find it simpler to list that things that are not acceptable?

I really would like some intelligent response to this thought.

all the best,

drew