I know it's politically incorrect to resist the either/or (us/them) category when to comes to politics, but that's precisely what I want you to try to do when you write here.
So, what is 'principled nuance?' Sorry to disappoint, but it's not some new liberal-speak neologism. In fact, I find much of today's liberal rhetoric ideological and polarizing.
Principled nuance is an individual approach to discussion that acknowledges the internal grey areas in one's opinion without abandoning core committments.
