The divisions in our nation have been growing for over 30 years.  The black civil rights movement ended Jim Crow segregation but it did not end racism in the hearts of some--(some Southerners never accepted they lost the Civil War and though they went underground their hatred continued).  Then in the 1980s the NRA began(?) encouraging people to arms themselves and take the law into their own hands.  Conservative talk radio began encouraging and enabling people who could see only their own view to go public.   President Reagan said repeatedly that "government was the problem"--(he could have said 'too much government is a problem).'  In the 1990s, after the Contract With America was presented and the GOP gained many seats in Congress, Newt Gingrich said "the Republican party can't govern properly unless it controls all three branches of government."  He was rejecting the working together and sharing of power that is at the foundation of our system of government.