Beyond the partisan stuff I think it's tough coming up with any definitions that please everyone. One factor is that both groups are not static thus preventing a solid definition. Wikipedia breaks Liberals into various groups.
Quote:
...One trend within liberalism has been a consensus towards the following:
* Political liberalism is the belief that individuals are the basis of law and society, and that society and its institutions exist to further the ends of individuals, without showing favor to those of higher social rank. The Magna Carta is an example of a political document that asserted the rights of individuals even above the prerogatives of monarchs. Political liberalism stresses the social contract, under which citizens make the laws and agree to abide by those laws. It is based on the belief that individuals know best what is best for them. Political liberalism includes the extension of the right to vote to women, non-whites, and those who do not own property. Political liberalism emphasizes the rule of law and supports liberal democracy.
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Wikipedia
And that is just the first one.
