The liberalism / leftism divide is actually a return to traditional terminology that dates back to post-revolutionary French politics. Leftists essentially want

The liberalism / leftism divide is actually a return to traditional terminology that dates back to post-revolutionary French politics. Leftists essentially want answers to the 'social question' (welfare) while liberals essentially want to protect 'liberties', primarily economic liberties. The weird hybrid between economic liberalism and light social democracy represented by the US Democratic party is basically an artefact of the electoral system, it's not actually a coherent politics. That's why there are such big divisions in the party itself.