If the GOP succeeds next week at the ballot box, politicians all over the country will conclude that they can advance their careers by vilifying minority groups, frightening voters predisposed to xenophobia, and dividing Americans. No incentive structure is more dangerous to a multi-ethnic nation. Politicians in other nations marshaling similar tactics have sparked sectarian violence, campaigns of ethnic cleansing, and civil war. Trump happens to preside over a country where such extreme outcomes are unlikely. But that does not change the character of his tactics or the moral obligation to stand against them.

I do not much like the Democratic Party. But I desperately want Republicans to conclude that the GOP harms rather than helps its prospects when it vilifies minorities, stokes the authoritarian impulses of its most frightened voters, and willfully divides Americans. Decisively defeating GOP candidates in the midterms is the surest way to send that message—while a Republican victory will encourage future campaign ads that even more closely resemble the work of D.W. Griffith.