No one speaking to an audience whose critical and logical faculties were fully aroused would indeed contend that because a certain body of people had chosen to call themselves Progressives, therefore a vote against them was necessarily a vote against progress.

But in the dim and shadowy region of emotional association a good name, if its associations are sufficiently subconscious, has a real political value.
Conversely, the opponents of a party attempt to label it with a name that will excite feelings of opposition.

The old party terms of Whig and Tory are striking instances of such names given by opponents and lasting perhaps half a century before they lost their original abusive associations.

More modern attempts have been less successful, because they have been more precise.

'Jingo' had some of the vague suggestiveness of an effectively bad name, but 'Separatist,' 'Little Englander,' 'Food Taxer,' remain as assertions to be consciously accepted or rejected.
The whole relation between party entities and political impulse can perhaps be best illustrated from the art of advertisement.