Liberalism and conservatism in America today don’t so much define coherent philosophies as temporary coalitions of ideas and interest groups flying in loose formation. Laissez fair economics, government regulation of sexual relations, a strong military and a willingness to use it: these ideas don’t necessarily go together. Neither does the combination of government intervention in the economy, sexual libertarianism, environmentalism and a dovish foreign policy.
Neither do the political parties map cleanly to conservative or liberal.
Here’s an interesting site that maps legislators spatially based on how often they voted with or against the majority. Here’s the last 50 Senate votes. You can see that although a clear party difference on economic conservatism/liberalism (using liberal in the New Deal sense). there’s a lot of more overlap in the social liberty dimension. The wing of the Democratic Party that’s more socially liberal than the most liberal republican is fairly small, and so is the group of Republicans that’s more socially conservative than the most conservative Democrat.
This puts things in perspective when one Republican candidate complains that another candidate is “out of the conservative mainstream.” Try and graph that spatially.