Few took Bill de Blasio seriously during the early days of his first campaign for mayor of New York in 2013. Early polls predicted that he would get no more than 11 percent of the Democratic primary vote against former city comptroller William Thompson and City Council Speaker Christine Quinn, both of whom enjoyed wider name recognition. Yet de Blasio beat them handily, and went on to defeat Republican Joseph Lhota in the November 2013 election with 73 percent of the vote.

It was a stunning victory after 20 years of mayoral leadership under Michael Bloomberg, a Democrat turned Republican turned independent, and Rudolph Giuliani, a staunch Republican. Other than a single term served by David Dinkins (1990–94), Bill de Blasio was the first unabashed progressive elected to City Hall in nearly a half-century. What distinguished him from every other candidate in 2013 was his adamant insistence that economic inequality was the defining issue of the day. His opponents did not seem to get that, but the voters did. The same voters also elected a progressive City Council, whose speaker, Melisa Mark-Viverito, aligned herself with the new mayor to advance their common agenda.

Like all modern mayors, Bill de Blasio likes to invoke the name of Fiorello La Guardia; but de Blasio is different from La Guardia. In fact, in the run-up to the last election, de Blasio accomplished something that none of his predecessors had, by building an electoral coalition that cut across the boundaries of race, class, and gender—the later broadly defined to encompass gays, lesbians, and transgender people. Surely, no chief executive better defined the important role that government must play in helping the needy than the Little Flower, but he had a mediocre record on race. He allowed the Housing Authority to be segregated, was blindsided when riots broke out in Harlem, and buried his own report on the angry eruption. We might add: La Guardia, who advanced landmark labor legislation as a congressman, did not believe that public employees should be unionized or engage in collective bargaining.

Mayor Robert Wagner instituted collective bargaining in 1954, and breathed life into the municipal labor movement, but his moderate, incremental style of liberalism left him unprepared to deal with the more militant forms of racial politics that accompanied the demands of Black Power activists in the mid-1960s. John Lindsay, his successor, responded to these pleas with enthusiasm. He was instrumental in incorporating African Americans and Latinos into the mainstream of city politics, and was the first mayor to speak out on behalf of women and gays. Lindsay, however, could turn a deaf ear when it came to white working-class residents from the outer boroughs, and he alienated just about every union leader in town. Two of the uglier episodes of his tenure involved racial conflicts with the United Federation of Teachers and the Patrolmen’s Benevolent Association. He never quite understood that an effective progressive coalition is just not viable without meaningful support from organized labor.

Bill de Blasio has a history of involvement with third-party, labor-oriented movements. Virtually every labor contract had remained unsettled when he took office, and he immediately acted to resolve them. Unlike Mayors La Guardia, Wagner, and Lindsay, de Blasio simultaneously has forged amicable relationships with most union leaders and representatives of people of color—a feat facilitated by the changing demographics of the city labor force. (David Dinkins, the city’s only African-American chief executive, did the same, but was hamstrung by the precarious fiscal situation he inherited.)

Moreover, unlike any of his three progressive predecessors, de Blasio does not have a Franklin D. Roosevelt or Lyndon B. Johnson in the White House to support his agenda with resources and legislation. His administration is an illuminating case study of the prospects for progressive local government at a time when efforts to help disadvantaged and marginalized communities are stymied by a hostile disposition in two-and-a-half branches of the federal government—a lesson on what mayors can and can’t do under the present national regime.

Washington’s retreat from a sympathetic urban agenda predated the arrival of Donald Trump. It goes back as far as the Jimmy Carter administration, and has proceeded virtually uninterrupted by various Democratic and Republican administrations, with the help of bi-partisan coalitions in Congress that have amended the tax code and regulatory policy to usher in the worst system of economic inequality in the free world. Big city mayors are left with the burden of dealing with the fallout of that inequality that manifests itself in homelessness, underperforming schools, crumbling infrastructure, inadequate mental-health treatment, and other societal injustices.

With its thriving economy, New York has been among the more fortunate urban centers in America. This has enabled de Blasio to spend more money on housing, homelessness, education, and social services than any mayor in New York history. He has certainly put his money where his mouth is. However, the loss of federal aid has made him more dependent on the real-estate and business sectors to advance his housing program, in which three of every four dollars is invested by the private sector. Some housing advocates believe he has not done enough to accommodate the needs of the city’s poorest residents. Homelessness is at a record high, and gentrification is displacing people who cannot afford rising rental costs in their own communities.

During de Blasio’s tenure, the unemployment and poverty rates have come down and earnings are up; there has been a simultaneous decline in crime, arrests, and citizen complaints against the police; universal pre-kindergarten is a reality, and student test scores continue to improve in the public schools.

De Blasio’s approval rating, nevertheless, appears stuck below the 50 percent mark. It will probably remain there. He draws some of the most severe criticism from his allies on the left, who want him to do more. Such a perpetual state of discontent on the left is what keeps New York’s progressive spirit alive, and is unlikely to subside. That malaise notwithstanding, de Blasio appears unbeatable as he faces reelection. Organized labor has built a wall of defense around him that no opponent appears able to penetrate. It was not that long ago when Mayor Michael Bloomberg built an invulnerable wall around himself by spending unimaginable amounts of his own wealth to become mayor as many times as he pleased. A lot has changed in New York in such a short period of time.

Running against the tide, de Blasio has demonstrated that economic progressivism is a winning strategy. He was one of the few Democrats in the country who seriously attempted to move presidential candidate Hillary Clinton in a similar direction in 2016, to the point that he withheld his endorsement of her until the last minute. That move cost him politically—at least for a while. The party gave former New York City mayor Michael Bloomberg a more prominent speaking role at the national convention than de Blasio, an incumbent Democrat in America’s largest city. Perhaps if the mainstream establishment of the Democratic Party had heeded the admonitions of people like de Blasio and candidate Bernie Sanders to recognize the economic hardship endured by Middle America and the poor, Donald Trump would not be sitting in the White House.

De Blasio is about to prove one more time that economic justice is an important issue to voters. The leaders of his own party need to hear that—not just for New York’s sake but, more profoundly, for the survival of other cities like Detroit, Baltimore, or Memphis that do not have stable local economies that enable them to deal with the symptoms of our growing inequality.