Several toxic screeds into his Minneapolis rally earlier this month, Donald Trump did what bullies always do and zeroed in on his chosen victim. That would be the 52,000 Somalis living in Minnesota. As dark-skinned Muslim refugees, they check all the bigotry boxes for the white nationalism of Trump’s Republican party.

“As you know, for many years, leaders in Washington brought large numbers of refugees to your state from Somalia without considering the impact on schools and communities and taxpayers,” Trump told a hooting, jeering crowd in the Target Center basketball arena. “You should be able to decide what is best for your own cities and for your own neighborhoods, and that’s what you have the right to do right now, and believe me, no other president would be doing that.”

For good measure, Trump singled out one of his standard villains, Ilhan Omar, as he strutted across a podium about three blocks from her Congressional district office. He called the naturalized citizen an “America-hating socialist” and a “disgrace”.

The political purpose of such rhetoric, of course, is to flip Minnesota from blue to red in 2020. And, contrary to many media reports of the recent rally, Trump has tried exactly the same gambit before. In the final days before the 2016 election, he declared to an adoring mob in a hangar at Minneapolis’s airport that the resettlement of Somali refugees was “a disaster taking place”.

Like any demagogue, Trump understands how to play on fears, in this case fears catalyzed by the arrest of several young Somali men in Minneapolis for trying to join Islamic terrorist groups abroad and the stabbing attack by a Somali in a shopping mall in the small city of St Cloud.

Trump also knew how to pointedly ignore the larger, normative story of Somalis in Minnesota. This supposedly alien implant actually came to the state through the principled efforts of Lutheran and Catholic resettlement agencies, which earlier had sponsored thousands of Vietnamese and Hmong refugees.

Somalis work in a variety of jobs – cashiers, skycaps, cab drivers – at the very airport where Trump whipped up rage against them. They have been successful entrepreneurs and enthusiastic founders of charter schools; they are socially conservative. Had the GOP not adopted nativism, racism, and Islamophobia as core precepts, the party might well have wanted to appeal to voters just like the Minnesota Somalis.

Trump’s hateful campaign pitch in 2016 nearly worked. He lost Minnesota to Hillary Clinton by merely 1.5%. So it is entirely plausible – scarily so – that the demonization of Somalis can carry the state for Trump in 2020. In a closely divided race, the state’s 10 electoral votes loom large.

Facing that prospect, Minnesota’s moderates, liberals, and progressives might want to make use of a historical precedent. Trump, as it turns out, is not the first merchant of intolerance to peddle his wares in the state, and not the first one to try to confront and belittle a young, inexperienced mayor, as Jacob Frey is in Minneapolis.

More than 70 years ago, the minister, presidential candidate, and wide-ranging bigot Gerald LK Smith made repeated trips to Minneapolis on behalf of his America First political party and Christian nationalist crusade. His foil during those incursions was Hubert Humphrey, initially as an aspiring politician and after 1945 as a mayor in his mid-30s who had never held elective office before.

The political geography of Minnesota back then was both totally different and fundamentally the same. It was different in the sense that today’s progressive Minneapolis was considered the most antisemitic city in the country – while the mining area of the Iron Range that is Trump country today was fertile ground for radical leftists. It is the same in the sense that an overwhelmingly white, Protestant population is prime to be turned against a racial, religious other.

When Smith came to town, that other consisted of Minneapolis’s small communities of Jews and African Americans, who huddled together in adjacent neighborhoods on the city’s North Side. They were penned in there by a pervasive system of restrictive covenants, and subject to rampant job discrimination. A Jew could not even join the city automobile club, and when a black first world war veteran bought a home in a white neighborhood in South Minneapolis, thousands of threatening locals besieged the house.

Humphrey fought back in both rhetorical and practical ways. In a public hearing on Smith’s request to speak at the municipal auditorium, Humphrey tore away Smith’s religious mantle, saying that no true Christian could be antisemitic because Jesus was a Jew. After a later Smith speech drew vigorous protests and nearly broke into violence, Humphrey opened his mayoral meeting room to welcome the dissidents.

Most of all, Humphrey forced the city to look at its heritage of discrimination unflinchingly through an extensive self-survey led by an African American sociologist. Humphrey pushed through one of the first fair-employment laws in the country. He fought his own police force, which was known for brutality and harassment against minority groups.

Such efforts launched Humphrey’s national political career and directly led to his successful drive in 1948 to have the Democratic party platform endorse civil rights for the first time. But it is also true that Humphrey catapulted into Washington so quickly with his Senate election in 1948 that he never finished the work of civil rights and human rights on his home turf.

The contemporary political figures who consider themselves in various ways to be Humphrey’s heirs – Mayor Frey, Governor Tim Walz, Senators Amy Klobuchar and Tina Smith – have been given a golden opportunity by Trump to renew and update Humphrey’s efforts. Those 10 electoral votes may represent an immediate prize, but the greater and broader triumph would be making Minnesota once more a firewall against the forces of hate.