Unfortunately, today's liberals have done a complete 180 from the philosophy and values of the classical "liberal" of the early 1900s and before, and now embrace the ideas of expanding the power of government into most formerly-private affairs, taxing the productive among us, abolition of private property rights, censorship and even punishment for thoughts, ideas, and speech terms, etc. While those now called conservatives embrace the ideas formerly held by the old "classical liberals" such as Locke.
Basically today's liberals have the idea that government (a) can, and (b) should do extensive lists of things to help people with ordinary, everyday problems; while conservatives believe that government should do only the things people (or groups) CANNOT do, which is a much more restricted list. In this way, the basic philosophies of today's liberals and conservatives (note I did not say Democrats and Republicans, which are not the same thing at all) have indeed diverged widely, and in ways that cannot be compromised.
What compromise is possible between someone who believes govt should be able to take far more from the wealty while taking hardly anything from the non-wealty (tax on incomes, either "progressive" or "flat"), and a person who believes that everyone has a right to keep what he earned and each person should pay to government in proportion to what he receives from government?
What compromise is possible between someone who believes a person should be punished more for what he was thinking while committing a crime ("hate crime"), vs. a person who believes punishment should be meted out only for what the lawbreakers DID, and what rights that lawbreaker intended to violate (say, murder vs. manslaughter)?
"The social contract exists so that everyone doesn’t have to squat in the dust holding a spear to protect his woman and his meat all day every day. It does not exist so that the government can take your spear, your meat, and your woman because it knows better what to do with them." - Instapundit.com