The moment Obama was elected the first Black President of the United States the wheels were set in motion to get the Reagan Democrats to fight for their survival. And I'm not even talking about Mitch McConnell's famous Washington restaurant meeting with GOP leaders to make Obama a one-term President by obstructing every legislative proposal of his even if Republicans support these.
Rick Santelli made that famous rant on the Chicago Mercantile Exchange after Obama assigned $200 billion of the bailout money to help homeowners who were under water. Santelli basically said do you want to pay for your neighbor's extra bedroom and bathroom with your taxes when they didn't deserve it? Obama are you listening. come join my movement of Taxed Enough Already. The TEA party was then born.
They were the dominant political movement in 2010 when the Congress and Senate went back to the Republicans. Then came the urban millennial backlash called the Occupy Movement. The rust belt democrat white male voters started to take form. Obama won in 2012 by a smaller margin than 2008.
The police shooting of innocent Black young people was part of the milieu. So Black Lives matter came to the fore. The rust belt Reagan Democrats who were also Bill Clinton's Democrats matured. Trump said a lot of bad stuff about war heroes, pu$$y grabbing, didn't pay taxes, filed for bankruptcy, etc. but what mattered is that his opponent seemed alien to them. Hillary only attacked Trump on Alicia Machado and the Gold Star family and his taxes, while the Russians and Julian Assange dumped those emails and Comey brought back the email server to life. Hillary ran away from Obama core (TPP, Middle East) while campaigning as Obama 3. She was on loose footing while Trump was on stronger footing (never mind the appeal to KKK and all te other bad stuff about shooting someone on 5th Avenue and not losing a vote).
So now you have the movement that Trump personifies and you have the liberal Trump himself. Knowing that he cannot bring jobs back, break treaties, repeal Obamacare, etc. is what will be the interesting fight in DC - Trump versus House Republicans. A good gauge will be to see how Mike Pence fares - will he be stronger than Ivanka Trump.