I see it as more of a class war. If they can keep the working class divided against itself, this would prevent them from uniting together to cast off the yoke of the upper classes. Hence the need to wall us off left vs right.

BTW, you might want to say: Portland, Oregon as there is another well-known Portland in the State of Maine and many others too

Here we would say for example: Philadelphia, Pennsylvania instead of Philadelphia, USA as there are more than one (Philadelphia, Mississippi Philadelphia, Tennessee etc.) nationwide :)