@Rockhead,
I don't think it is the core, but I have observed that liberals have a very tough time explaining their core values or principles and what drives their philosophy. Part of the problem with liberalism is that it does not have good core values or principles, because it is very "squishy" or emotionally based, and changes to fit whichever way the political and cultural winds are blowing.
I keep prodding you and encouraging you, and giving you a chance to explain yourself, Rockhead, to clarify what you believe and why you believe it. Most people that are proud of what they believe would jump at the chances and questions I have given you. One of the frustrating things about debating liberals is their dodging and weaving, and the difficulty of pinning them down or defining what they believe.