Even if people agree to buy into this whole "this election is special" premise, I think people would be well within their rights to riot in 2020, if they hear one more time that that election is special, too, and they must once again vote Democrat ("because who else are they going to vote for?!")
Because when elections become "special" all the time, it means they really aren't. And it means the problem is systemic, and it's that systemic issue that needs to be addressed before voting against any particular candidate. Otherwise, these problems are never going to end. "Fix Democracy First" - as Lessig once believed (like until earlier this year) before he also started thinking that people should just shut up and vote for Clinton already.