Two things, Gerrymandering is said to be Congressmen choosing their voters instead of the voters choosing their congressmen.
The Democrats rode that uneducated train for a long time. From 1980-2012 not a H.S. graduate voted Democratic in presidential races. College grads went Republican from 1988-2004, 2008 for Obama, 2012 for Romney and in 2016 for Hillary.https://www.nytimes.com/elections/2008/results/president/national-exit-polls.htmlhttps://en.wikipedia.org/wiki/2012_United_States_presidential_election#Voter_demographicshttps://www.cnn.com/election/2016/results/exit-polls
There's a lot more info in the links that may or may not interest you.
For someone who follows numbers, history etc. It's easy to spot these. If just the educated voted, G.H.W. Bush would have won reelection in 1992 and Dole would have become president in 1996. G.W. Bush won college grads twice, Obama in 2008. But the educated would have put Romney in as president in 2012. Now come to think about it. Romney would have been the GOP candidate in 2016, no Trump. So perhaps the educated knew exactly what they were doing and who they were voting for.
Now why independents vote the way they do, I really don't know. It's all speculation. I only know what history shows. I find independents fascinating, Republicans and democrats, boring and dull.
I'll add this, every individual has their reasons for voting the way they do. Those reasons are important to them. Although many may think their reasons are asinine.