In his dogged pursuit of the presidency, Donald Trump has turned the 2016 race for the White House into the most canine election ever. Trump has a strange obsession with man’s best friend, which pops up frequently in bizarrely hostile metaphors. “Mitt Romney had his chance to beat a failed president but he choked like a dog,” Trump recently tweeted—a somewhat baffling comment, since dogs aren’t especially known for choking. But it’s in keeping with the presumptive Republican nominee’s longstanding habit of using dogs as a touchstone for lowliness and debasement—a habit that reveals a lot about Trump’s view of humankind, about the strange campaign he’s running, and about the stark choice Americans will be making in November.

Trump has frequently referred to people being “fired like a dog” (“I hear @EWErickson of Red State was fired like a dog”). And on Monday morning Trump himself fired his campaign manager Carl Lewandowski in the most humilating manner possible, having him escorted out by security like a dog. But Trump also talks about people being degraded in other ways that are supposedly dog-like, as in tweets like this: “Union Leader refuses to comment as to why they were kicked out of the ABC News debate like a dog.” Or this: “Robert Pattinson should not take back Kristen Stewart. She cheated on him like a dog & will do it again—just watch.” Or this: “@BrentBozell, one of the National Review lightweights, came to my office begging for money like a dog.” And of course, Trump is known to describe women he finds unattractive as “dogs.”

If dogs are a big part of Trump’s mental landscape, his supporters push it one step further. “Trump that bitch” is an anti-Hillary Clinton slogan frequently seen on signs and T-shirts at Trump rallies. “Bitch” is of course a misogynist slur, but it derives from the term referring to a female dog. By contrast, Hillary Clinton’s husband is more affectionately known to his fans as “the big dog”—a phrase suggesting a tolerance for his foibles, a courtesy rarely extended to his wife. Hillary Clinton’s own problems as a politician can be summed up by the fact that her opponents feel free to throw around the b-word, but among her fans there is no corresponding affectionate term comparable to “the big dog.” She doesn’t even get credit for editing Dear Socks, Dear Buddy, a collection of letters sent to the White House cat and dog.

The use of canine insults by Trump and his supporters shouldn’t be dismissed as just juvenile behavior. It actually offers a revealing glimpse into Trump’s worldview. Trump practices dominance politics. He loves to taunt his rivals and even his supporters, as in the sad case of Chris Christie. This is how Trump proves he’s the boss, the leader of the pack, the top dog. And to keep his pack in line, the top dog has to remind everyone that they are lowly dogs.

But there is something more at work. The dazzling literary critic William Empson, who was perhaps more alive to shades of diction than anyone else who has ever analyzed English literature, discussed the evolution of the word “dog” in his 1951 book, The Structure of Complex Words, making points directly pertinent to Trump’s peculiar usage. Empson traced a revolution in the usage of the word “dog” in literature that took place in the seventeenth century. The shift was from a harsh, unforgiving view of dogs that dominated the sixteenth and early seventeenth century, toward a much more positive and forgiving view of dogs that emerged after the restoration of the Stuart Monarchy in 1660 and flourished in the eighteenth century.

The improved image of the dog is tied to a larger shift in ideology, a move from a view that life is bleak and pitiless to a more optimistic sense of human (and canine) nature. In his rhetoric, Trump is a throwback, using “dog” almost exclusively with its earlier, nasty connotations—and revealing the bleak, pitiless view of the world that characterizes his whole approach to politics.

In this, Trump is surprisingly Shakespearean. In the sixteenth and seventeenth century, the word “dog” was almost always used as an insult in English literature. There’s no positive depiction of dogs in Shakespeare’s work, with the partial and ambiguous exception of Timons of Athens (where a cynical philosopher is linked, as was habitual since antiquity, with dogs, who were seen as natural cynics). “They flatter’d me like a dog,” King Lear said about two of his daughters, words that anticipate Trump’s own language. In Anthony and Cleopatra we hear about “Slave, soulless villain, dog.” And in Henry V, “egregious dog? O viper vile!”

Writing in Psychology Today, Clive Wynne argued that “Shakespeare hated dogs.” But Shakespeare’s contemporaries were no kinder toward dogs than he was. As Empson makes clear, his hostility towards dogs was rooted in the widespread sense in Early Modern Europe that life was a brutal, elemental affair, with dogs standing in for a Hobbesian world of strife and struggle, in which human nature was likely to revert to the wildly untamed and animalistic.

Through this lens, we can see this election as effectively a battle between two clashing world views about dogs and life. Is America going to the dogs, as Trump’s rhetoric about national decline suggests? Such a world requires a tough master. Hillary Clinton is herself very tough, but also has a more forgiving side, which emphasizes not the need for the pack to get in line but rather to help each other.

Using Empson’s schema, it’s evident that Trump’s usage of dogs is rooted in a sixteenth and early seventeenth-century view of life as constant strife, with dogs as the bottom of the heap, symbols of human baseness. And Trump is generally an unforgiving man, for whom mercy is alien. After all, Trump initially hesitated to say what his favorite verse in the Bible was—but finally settled on “an eye for an eye.” His unforgiving worldview extends far beyond dogs, of course. He is similarly harsh with minority groups he wants to deport or block from entering America, as well as allies he thinks are ripping America off. In his speeches, Trump sounds like he’s meaner than a junkyard dog.

Trump’s barking-mad rhetoric served him well in the primaries, where he was able to get the GOP base to join his howls. But Trump’s strident language is likely to hurt him in the general election, where the broader electorate is likely to see him not as the leader of the pack but as a mad dog on the loose. Trump’s harsh view of humankind, expressed through his dog metaphors, helps to explain why his campaign is so short on vision and uplift, and so long on vitriol. The real question for the election is whether America believes, as Trump does, that we live in a “dog-eat-dog” world—or whether, perhaps, Hillary Clinton can help create a more generous world, where “every dog has its day.”