Donald Trump’s political speeches of late are chock full of warnings about “the threat from within” posed by his myriad opponents – those he decries as “vermin” out to destroy the US and the American Dream. He routinely promises to crush his critics and “make America great again.” As always with Trump, there’s a method to his madness. Historian Heather Cox Richardson argues that Trumpism claws at American democracy’s true roots – at what she describes as “the idea that a nation can be based not in land or religion or race or hierarchies, but rather in the concept of human equality.”