Though there clearly is a sense in which current American politics is very polarized, there's another sense in which our levels of polarization are almost trivial compared to 1930s France. We don't have a substantial revolutionary Communist movement here in the United States, nor a monarchist movement, nor do we have an officer's corps that's generally skeptical of civilian command and republican governance. Indeed, even compared to the United States of forty years ago when you had a lot of votes going to George Wallace on a white supremacist platform and substantial intellectual support for the idea of convergence between the Soviet and American economic models, our politics is conducted across a pretty narrow ideological spectrum.
What's new in America isn't polarization in that sense, but the rise of partisan polarization organized around two fairly coherent political parties. The good news about this is that it's mostly an inevitable consequence of the decline of Jim Crow.
Points taken. But doesn't that make the polarization all the more toxic? Because it's based less on substantive policy or ideological disagreements than on red/blue identity.
My own substantive positions, for example, are mainly unchanged over the last few years. I'm a low tax, free market, fiscal conservative who likes limited government, and effective use of military power. I find Islamism to be as dangerous an ideology as any I have studied. My critique of the Iraq occupation is less a function of an ideological transformation as the consequence of watching it unfold, and seeing its ineffectiveness in the war against Islamist terror (as well, of course, as the astonishing incompetence with which it has been managed). I can live with RomneyCare; I'm anti-Roe but fine with first trimester legal abortion; I'm against affirmative action; I'm for states' rights; I'm for entitlement reform; and my support for a gas tax is a consequence of the accumulating evidence on climate change - again, not some ideological shift, an empirically-based adjustment.