Where once the political spectrum consisted mainly of the differences between Democrats, liberals, Republicans, and conservatives, there is now a clear distinction between liberals and the left and the riff at the southern border is exposing the desired results of both as well as dredging up many previously hidden swamp dwellers. Both "L's" reside squarely in the Democratic party with the left quickly taking control and a lead role in party policy and behavior.
Before the surprise Presidential election win of Donald Trump, both Democrats and Republicans could get away with pretending to want a secure border while hiding their opposition to border enforcement. They and the rest of the Washington establishment swamp never intended to stop the flow of illegal immigration into the U.S.