A lot of the polarization is not at all new, as @Jeruba and others note. However, the quality of discourse – and the average level of knowledge and awareness of how our constitutional government should work (and does work) – have decreased markedly in my lifetime. So when presidential candidates such as Donald Trump and Bernie Sanders can stand in front of huge constituencies who seem to believe that either of them can actually deliver on even a tiny percentage of what they promise (they cannot), or who can discount the nonsense they hear from their candidate “because the other side is worse”, and leave that as an acceptable argument in support of “their side”, then I fear for the future of the republic.
Listening to the arguments that I hear between, say, Trump and Sanders supporters is like listening to a drunken argument between Red Sox and Yankees’ fans in the grandstand at a baseball game – except the fans can usually muster somewhat more cogent arguments based on actual, verifiable statistics of the players and teams in question. Trump and Sanders supporters leave me wondering who reminds them to inhale and don’t forget to exhale, too! every day. Don’t think, based on that diatribe, that I have any love for Clinton or any of the other nominal Republicans, either.
For the most part, I’m simply appalled that though most people on both sides of any argument about most of our current problems in the USA agree that it’s the government at fault, everyone seems to think that the answer is “more government – just ‘my kind’ of government.”
Apparently, not many people can actually think any more, and even fewer want to. Present company mostly excluded.