One of the most underappreciated aspects of Zohran Mamdani’s successful primary campaign for New York City mayor was its connection to small business. He stopped by halal carts and bodegas and asked what challenges they faced. It is the kind of outreach that teaches policymakers about real problems in our economy and can help build trust and lasting relationships.

It is also too rare.

Fighting for an economy where small businesses can thrive was once core to the Democratic Party. Democrats built a lasting coalition by shifting economic power to ordinary Americans, checking the power of big business, and expanding the middle class. But for decades, the party has largely ceded issues important to small businesses to Republicans.

During the New Deal, small businesses were a key part of Democrats’ coalition, with President Franklin Roosevelt championing “economic freedom for the wage earner and the farmer and the small-business man.”

The government gave workers greater rights and protections and checked the power of big business in banking, retailing and agriculture. Placing checks on big business while ensuring fair opportunity for labor and small business was recognized as a path for ensuring dignified work and growing the middle class.

Since President Bill Clinton, however, the mainstream of the Democratic Party has too often treated small business as little more than a talking point. Mr. Clinton may have heaped praise on “the entrepreneurial spirit” of small-business leaders, but his embrace of President Ronald Reagan’s “big is better” antitrust policy fueled industry consolidation and allowed monopolists to squeeze out smaller rivals. Clinton-era deregulation also spurred a soaring number of bank mergers, reducing the number of places where an entrepreneur could get a loan.

From 1980 to 2020, as the share of the economy accounted for by small businesses fell, big business interests began spending heavily in elections, bending the ears of many Democrats and sometimes skewing how they saw the economy. Even when Democratic policies were better for small businesses than Republican policies, Democrats didn’t make a sustained effort to court small-business owners and turn them into a reliable base of support.