Politeness comes from social solidarity: it is a consequence of social harmony, not a precursor. What if the polarization represents actual, fundamental disagreements on politics and, at root, moral axioms? Being polite hasn't done much for the respectable right for the last fifty years.
I would rather focus on solutions like secession or federalism that allow groups of people with different and irreconcilable moral axioms to simply leave one another alone to build the social/political structures they would prefer.
I would rather focus on solutions like secession or federalism that allow groups of people with different and irreconcilable moral axioms to simply leave one another alone to build the social/political structures they would prefer.