Explain the influence of Steve Bannon on Trump's administration and the role of the Republican majority in government.
Trump, as insane as he is, is simply a puppet of Steve Bannon who once called Trump "a useful tool" for furthering his extremist agenda. 
Fortunately, at least until Trump gets his Supreme Court pick, there is still one institution of government that can retain some sanity in America. The House and Senate with Republican majorities are bought and paid for, so don't expect them to reign in Bannon.