Ask HN: Why US major parties don't have names descriptive of their actions?

I noticed that the US biggest parties are democrats, and republicans...<p>The democrats, don't push for democracy.<p>And the government is already a republic, thus the republicans do not have to push for republicanism either.<p>Why the parties are not something like progressives and conservatives?<p>Or liberals and nationalists? Or anything else that better reflect their values?