Trump Is Baiting Democrats, by David Frum.
Plan or no plan, though, Trump hit the Democratic Party at its point of vulnerability. He is driving it toward ever more radical outcomes: against the enforcement of immigration laws and for the acceptance of virtually all border crossers; against the bread-and-butter issues that will mobilize the voters the Democrats need and for the symbolic actions that will gratify the educated urban progressives who live in the safest Democratic districts in the country.
Who is leading and who is following is debatable. Trump has now joined the left in its dance towards tribalism, simply by opposing it.