Arthur Brooks says that liberals are heartless. Errrr...sort of. Anyway, you might be able to say they're mean spirited.

Let's dispense with righteous rhetoric and look at what really counts: behavior, starting at the level of heart in personal relationships. Consider two groups of people under age 30: those who say they are liberal or extremely liberal, and those who say they are conservative or extremely conservative. According to General Social Survey in 2004, liberal young Americans are significantly less likely than the young conservatives to express a willingness to sacrifice for their loved ones. For example, progressives under 30 are significantly less likely than young right-wingers to say they would prefer to suffer rather than let the one they love suffer, that they are not happy unless the loved one is happy, or that they would sacrifice their own wishes for the one they love. (The practical implication of this is that you might want your daughter to marry a Republican.)