There is so much this thread that is raising my blood pressure this fine Election Day morning...
First, Munroe can kindly butt out. I know of no American clamoring for a British model to weigh in with diktats on our election.
Second, the poll Trump seems to have been referring to when claiming 40% support from black people is Rasmussen's daily tracking poll one day in October.
Two points on that: Rasmussen is a partisan Republican outfit, and this was a daily tracking poll, not a completed formal poll.
So for a formal poll, callers will be in the field over a period of days to get a large enough sample for statistical significance. And they'll try hard to get enough respondents from each of the groups they're studying to make each sub-category statistically significant. This is impossible to do in one day.
A tracking poll is something different. It takes a daily "temperature" or mood of the public. As that changes over time it can be interesting to watch. But no one who understands polls, or math, would point to the inevitably small sample of a sub-category of respondents in a daily tracking poll and make sweeping claims that they represent the views of that group overall.
I can't find the number of respondents to that poll, so "40%" might mean 2 of the five black people they called that day approved of Trump.
The number is not at all in line black approval in the masses of polls we've had over the past 2 years, and there is no reason to believe there has been some amazing sudden shift because black people now love Brett Kavanaugh and caging children at the border.
Oh, and the Washington Times is part of the right wing news machine, like Fox News. It is not an impartial source.
I will come back later to address some of the Democratic stuff.