Steve Bannon has declared war on the establishment, but why should we care? President Donald Trump’s former chief strategist plans to support challengers against incumbent Republican senators in the 2018 midterms, a move that has received plenty of media attention and responses from both Trump and Senate Majority Leader Mitch McConnell. Bannon fancies himself a kingmaker, but it’s unclear if he actually wields that power. “When you want to talk about why there’s no repeal-and-replace,…