Rep. Greg Casar, D-Texas, is chair of the Congressional Progressive Caucus and is pushing a “New Affordability Agenda” that addresses issues from oil prices to corporate influence on elections. Steve Bannon is a former strategist for President Donald Trump and a proponent of “economic nationalism” who wants to limit the power of global corporations over working-class Americans. One personifies the populist left; the other, the populist right. Bu…