The Althouse challenge: explain inconsistent compassion

Okay, I'll bite.

Ann Althouse challenges the blogosphere to answer the question Ralph Nader posed on "Crossfire" the other day: why aren't Republicans and Democrats consistently compassionate?

Three reasons:

(1) Because they are human beings, and human beings are not consistently anything--except, perhaps, inconsistent.

(2) Because they are politicians, and many of their decisions are strategic rather than moral, designed to get themselves elected and then re-elected.

(3) Because (when they're not following rule #2 above) they believe that adherence to certain overarching principles will lead to a greater good for all, and therefore they are ready to sacrifice compassion towards certain individual cases at the altar of this common greater good.