The specter of White nationalism is real. We ignore it or discount it at our peril.
The problem already is upon us, as Benji Hart explains in White Nationalism Lives and White People Need to Fight It:
More recently, white nationalism has been linked with a spate of police murders. Scott Michael Greene, who killed two officers in Iowa in late October, allegedly did so because he was enraged that Black athletes kneeling for the national anthem had not been arrested. Over 70% of police killings in 2016 have been carried out by white men, a fact around which many have noted a telling silence among conservatives. The FBI itself has been warning of growing white supremacist activity within law enforcement for more than a decade, and some pundits have gone so far as to call white nationalism the greatest standing threat to national security.
Impending demographic change undoubtedly will worsen the threat. Whites will be in the minority by 2042, according to projections. Emily Schwartz Greco explores the connection of that reality to white nationalism in Will Trump Target Both Documented and Undocumented Immigrants?