Gag Rule and Politcal Name Calling

I've been reading Lewis Lapham's book Gag Rule these days and even though I'm only 2/3 of the way through, it's already impressed me. One point that struck me is Lapham's description of the terms "liberal" and "conservative" in the book:

"The meanings of the words 'liberal' and 'conservative' have been so mercilessly abused over the last twenty years that they offer more information about the person who employs them as insults than they do about the person on whose head they fall like stones. To say that A is liberal or B conservative is to say nothing intelligible about his or her politics, conduct, occupation, place of residence, or record of prior arrests."

I have had the discussion with at least one person and, when you push those words at all, most definitions collapse. The most coherent thing I can come up with is something about the epistemological foundations for a person's thought. Of course the so-called neo-cons are a lot closer to classical liberal thought (rooted in rationalism more than tradition/empiricism) in that sense, thereby limiting even that description.

What are "liberals" and "conservatives" today? We all seem to know them when we see them.