Some good news.
It's nice that there's more data at hand to disprove the people who keep claiming that "All of Trump's voters will never abandon him because they're all racists/xenophobes/cultists/etc.
They aren't abandoning him. They're simply a bit less enthusiastic than before.
I don't think you're seeing the big picture here. Donald Trump lost the popular vote to the second most disliked candidate in modern presidential history (second only to him) and won the EC by 80,000 votes in three states; all less than 1% margins.
If just 10% of his base abandons him by 2020 then he's screwed.
No, your talking about his soft supporters (such as the Obama-Trump swing voters that obviously exist even though Dailykos pretends they don't) rather than his base. Very different groups of people.
