Damon Linker, The Week:
Lest Democrats succumb too quickly to schadenfreude at the prospect of the GOP breaking into two and clearing a path to landslide victories for the Donkey Party, they should ponder a couple of recent New York Times stories on Trump’s appeal to a “certain kind of Democrat” — namely, a working-class white Democrat with strong union ties. To test the thesis of these articles, Democrats should watch closely during upcoming open primaries to see how many Dems cross over to vote for Trump.
If the number comes to anything more than a trivial amount, that would open up a chilling possibility: that the ethnic-nationalist third party emerging from the GOP could draw support from the Democrats as well, effectively redrawing the ideological and demographic shape of both major parties.
That could herald the most significant change in the American political system — and inaugurate a period of greater political instability — than this country has seen in a very long time.