Donald Trump won a convincing victory over Kamala Harris largely due to record support from Black and Latino men. Trump won these votes because of, not in spite of, his immigration policies.

These predominantly working-class men intuitively understand that mass migration depresses their wages, increases competition for jobs and housing, and overburdens their local communities.

President Trump and Congress can deliver for these voters — and all working Americans — by reducing overall immigration levels. That means preventing illegal immigration and lowering annual legal admissions. Reducing legal immigration is exactly what another Republican president and Congress did a century ago — and it led to massive economic and political gains for Black Americans.

The Immigration Act of 1924 signed into law by President Calvin Coolidge drastically reduced the number of foreign workers arriving on American shores, especially from southern and eastern Europe. Annual immigration levels dropped nearly 60%, from 700,000 in 1924 to 295,000 in 1925. Over the next four decades, immigration averaged less than 200,000 per year.

As a result, factory owners and hiring managers had no other option but to hire Black workers from the American South. After the law passed, roughly six million Black Americans hit the rails and roads in a “Great Migration” northward to a chance for better jobs and greater wealth. Labor unions opened up to Black members, who could now extract better deals from employers.

Between 1940 and 1980, Black men’s inflation-adjusted incomes expanded four-fold, nearly twice as fast as white men’s incomes. The number of middle-class Black Americans more than tripled.

As Black Americans’ economic situation increased, so too did their political power — eventually putting them in a position to bring down the Jim Crow regime and gain full civil rights under the law.

Contemporary Black political and labor leaders recognized that mass immigration was hurting their economic interests.

“This country is suffering from immigrant indigestion,” pronounced A. Philip Randolph, the great Black union leader. “It is time to call a halt on this grand rush for American gold, which over-floods the labor market, resulting in lowering the standard of living, race-riots, and general social degradation.”

This flood of competition explains why Black leaders strongly supported the 1924 law. Just one year after it passed, Randolph’s The Messenger — the national-circulation, Black labor unionist magazine — declared, “Immigration from Europe has been materially cut, which means that the yearly supply of labor is much less than it formerly was. This gives the organized workers an advantage, greater bargaining power by virtue of this limited supply.”

Five years after the legislation passed, W.E.B. DuBois wrote in Crisis magazine of the National Association for the Advancement of Colored People, “(T)he stopping of the importing of cheap White labor on any terms has been the economic salvation of American Black labor.”

The end of the Great Wave of European immigration allowed for the formation of the Black middle class. The resumption of mass immigration in the second half of the 20th century has contributed to the diminution of the middle class, hitting Black Americans especially hard.

In 1965, Congress transformed the nation’s immigration laws in a bid to eliminate national origin quotas, which functionally prohibited immigration from Asian and African countries and greatly reduced the number of immigrants coming from southern and eastern Europe.

Unfortunately, the Hart-Celler Act unintentionally ushered in today’s era of mass migration. A second “Great Wave” that again has disproportionately impacted Black Americans by introducing competition for jobs, thus reducing both employment and wages.

There is ample evidence of the harm mass immigration has caused to Black Americans. Harvard economist George Borjas analyzed data from 1960 to 2000 and found that “a 10-percent immigrant-induced increase in the supply of a particular skill group reduced the black wage by 4.0 percent, lowered the employment rate of black men by 3.5 percentage points, and increased the incarceration rate of blacks by almost a full percentage point.”

A 2010 report by the United States Commission on Civil Rights found that illegal immigration reduces “both wages and employment rates for low-skilled American citizens, a disproportionate number of whom are black men.”

There is a reason President-elect Trump expanded the size and breadth of the Republican voter coalition, particularly making significant gains with Black and Latino voters. The negative effect of mass immigration hurts all American workers, which is why working Americans voted for their economic interests and rejected the Harris campaign’s attempt to divide and divert their attention from the open-borders policies in place for the past four years.

President Trump ran on a promise to fix America’s broken immigration status quo. Working-class voters of all races gave him their votes. And their livelihoods depend on him keeping his word.

Eric Ruark is the Director of Research for NumbersUSA.