Assume bad things happen in 2016 scaring white people so much that they vote for Trump en mass. The map looks something like this.
No way does Trump win either Michigan, Minnesota, or Wisconsin. Michigan has a larger percentage of blacks than any non-Southern states other than Delaware, Maryland, or Virginia (I now consider Virginia a Northern state). Of course this is no landslide, basically Kerry 2004 with New Mexico and Pennsylvania exchanged. Minnesota swings less than any other state, and the GOP is now toxic in Wisconsin.
I see Donald Trump as a Republican mirror image (except for being a rake) of Jimmy Carter, an 'outsider' who has very specific ideas of how to change America and unable to achieve them -- and having no Plan B. There might be something to running the federal government like a business -- except that justice, diplomacy, welfare, and the Armed Services cannot be run on profit-and loss bases.
The only effective President who had little-to-no experience in elected office who was at all effective since the Civil War was Dwight Eisenhower. Ike at the least had the difficult task of lobbying for funds in a Depression economy with a war-loathing populace, so he got some idea of how Congress works. Trump has no legislative experience, and no experience as a government executive even in a cabinet position.
They might have done well in 'Congressional and other' elections in 2016 -- but he will have to get miracles and dodge any possible economic downturn in 2017 and 2018 to avoid a scenario analogous to 2006 for Congressional Republicans. Get an economic downturn and have no idea of how to stop it except doing more of the same to intensify hardships for potential voters, and the Democrats will have elections like those of 1930.
Donald Trump is a crony capitalist. If he should sign off on the destruction of the welfare state while cutting taxes for the super-rich, then he could be Herbert Hoover, Version 2.0
Even poor, white Christian fundamentalist Protestants in the South have their limits. An image of America which looks like some old Bible-related movies of the 1950s in which amoral elites indulge themselves with no limits while the masses suffer extreme poverty will create plenty of opportunities for Democrats.
Republicans would have nobody to primary him in 2020 if the economy goes sour. If the situation is more like 1980 in which Donald Trump has an administrative mess and no clue of how to solve things, then he will be weakened in a primary. Either way he loses. See "1932" and "1980".
FDR, Version 2.0... someone who has resisted the national trend of austerity for the poor and enhanced indulgence for elites, should America have the start of a Great Depression, Version 2.2. If it is simply an administrative mess, then look to Barack Obama, Version 2.0 as a memory of the last somewhat-effective President.
...imagine an electoral map in which the Democratic winner wins all but roughly 50 electoral votes, because that is what 1932 and 1980 maps were. Basically take all states that Carter won in 1976 and Obama won in 2008 and add Arizona.
