Higher income earners are more likely to vote Republican

Contrary to the misconception that high income states being Democrats suggests higher income earners are not more likely to vote Republican, within a given State (whether led by Republicans or Democrats), one does indeed observe that the likelyhood of voting Republican increases with income.
If that is true, then income polarisation can reasonably be expected to lead to more political polarisation, which – all other things held constant, would provide a plausible explanation for the deadlocks that increasingly characterise Contemporary American Politics.