The election post-mortems are underway. Bernie would have won, white lash, Trump's victory means all kinds of things (it's an indictment of liberalism, it's proof of whatever pet theory, etc.)
Most of the post-mortems are wrong. If things play out slightly differently and she wins, nobody is saying this was an indictment of liberalism.
Here's my take: More of the population voted for Romney in 2012, McCain in 2008, and Bush in 2004 than voted for Trump in 2016. At present, the raw vote count is Trump 60.1 million, Romney 60.9 million, McCain 59.9 million, Bush (04) 62 million. Remember that every year the population is larger, so in 2008, McCain earned a higher proportion of the vote than Trump, and in the other years, we don't even need to adjust for inflation.
There's about 60 million GOP voters that show up in election years. A lot of experts thought that Trump would not be able to turn out that base, after-all much of that 60 million is religious conservatives and evangelicals. Would those people really all turnout to vote for the beauty-pageant creeping, grab 'em by the pussy, thrice married, recently pro-choice reality star? Well, turns out that Republican voters will all hold their nose and vote for team Republican. They don't care. No matter what candidate the GOP runs, they will vote for team red because that's what politics is now, a team sport. You might not like the domestic abuser on your football team, but you're probably not gonna stop rooting for them.
Trump did not win because he won over the masses, this wasn't a vast populist movement, he didn't win over independents or centrists. Trump won because the right showed up and the left didn't.
Obama in 2008: 69 million votes. Obama in 2012: 66 million votes. Hillary in 2016: 60 million votes.
Trump performed about as well as "generic republican," in fact he probably under-performed. He garnered a smaller slice of the Voting-age-population than the GOP nominee did in the last three presidential elections (2000 had very low voter turnout). Trump actually lost ground, getting fewer voters than Romney, in the
following states: Alaska, Arizona, California, Colorado, D.C., Georgia,
Idaho, Illinois, Kansas, Maryland, Montana, New Mexico, Oregon, Utah,
Virginia, and Washington.
The difference in this election was that the middle and some of the left didn't show up. The middle didn't pick Trump, the middle didn't like anyone and stayed home, and the left lacked enthusiasm for Clinton and didn't get out the vote.
BUT! Trump flipped a bunch of Blue states! He must have tapped into X,Y,Z.
Look to Wisconsin for example. Trump got 1,409,467 votes to Hillary's 1,382,310. Last time out
Wisconsin went 1,407,966 for Romney, and 1,620,985 for Obama. Trump won
Wisconsin while getting only 1,501 more votes than Romney. The regular
Republican voters showed up to vote for team Republican, regardless of
the candidate. But 238 thousand people that voted for Obama last time
didn't show up.
The story is the same across the rust belt. The McCain and Romney
voters voted for Trump. They're loyal to the party and don't listen to
what anyone has to say. The left is more fickle and when the left doesn't put up a
candidate they're excited about, they don't show up. The states that
flipped largely did so not because Trump won a lot more votes there, but
because Hillary lost them.
In Georgia, Trump garnered 2,078,064, while four years ago Romney got 2,078,688. Trump should have picked up more votes just because of the increased population, yet he did worse than Romney. This is how big team-red is in Georgia. Doesn't matter who the candidate is. Minnesota, Romney: 1,320,225 -- Trump: 1,321,120.
Team red is a defined size. Regardless of the starting QB they trot out, they have a set number of fans. Team red votes for team red. The difference in this election was not more people voting for Trump or for Republicans. The difference was a lack of enthusiasm for Clinton, and Team Blue is fickle. Team Blue is full of bandwagon fans that show up when Team Blue has a star player.
Voter turnout was a 20-year low. Only 55% showed up. For comparison, to reach the same voter turnout level we had in 2008, more than 18 million more people would have had to vote.
Only 26.3% of eligible voters actually voted for Trump (less than Hillary's 26.5%), and 28% of Trump voters, in exit polls, said they were voting against-Hillary and not for-Trump. Take those voters out of the equation and that leaves only about 19% of the country voted Pro-Trump. Less than one-in-five eligible voters really wanted Trump.
Assuming the Democrats don't rig their next primary, the Democratic nominee that emerges in 2020 will do so without Clinton's baggage, without the e-mails, without the fatigue of being in the public spotlight and the crosshairs of the Republican propaganda machine for 20+ years, and will win the primary because he or she generated enthusiasm and turned out the vote in the Democratic primaries.
I think we can also expect some Trump fatigue, as I expect his presidency to be plagued by scandals and gaffes. Even if it isn't, a President typically performs worse in their re-election bid than they did in their first run, and the party in power loses enthusiasm. Underdogs do a better job of turning out the vote, but victories breed complacency (see this election and the complacency of the left).
Changing demographics (older more conservative population dying off and being replaced by younger people that are far more likely to be liberal, as well as racial trends) point to stronger and stronger performances on the left.
If I had to guess, I'd say that Trump turnout in 2020 will probably be about the same: 60 million votes. The voting-age-population will probably increase by around 8 million people, and voter turnout was quite low this cycle, so this number is subject to change. But fundamentally the GOP turns out around 60 million people in each election, regardless if the candidate is a squeaky-clean Mormon former-governor with some real qualifications or a pussy-grabbing, pageant-running, casino magnate with a penchant for 3 am twitter feuds. The right shows up to vote team red. As long as the Democrats run a candidate with a pulse and less baggage than an international flight, they'll defeat Trump in 2020.
If the left produces a candidate that really energizes and inspires in the way Obama did in 2008, and simply extrapolating Obama's vote share to 2020's projected voting-age-population, then Obama 2.0 can expect to receive 78 million votes. Bump it to 80 if you want to account for the fact that the dying voters are pretty red and the 14-17 year olds are quite blue.
The fundamentals for the Dems are strong. They just need to pick a candidate that motivates people to show up to the polls and Hillary wasn't it. Hell, if they find a random person that can speak to a crowd, read a prompter, doesn't have a ton of baggage, and has a last name of "Hindsight" -- Hindsight 2020 -- defeats Trump in a landslide.