Lawrence B. Glickman is Stephen and Evalyn Milman professor of American studies in the department of history at Cornell University. He is author, most recently, of Buying Power: A History of Consumer Activism in America (University of Chicago Press) and the forthcoming "Free Enterprise: An American History," (Yale University Press, 2019).

The New Deal is back.

Nearly a century after President Franklin D. Roosevelt began his effort to revive the American economy through government programs, Democrats are once again becoming fans of Roosevelt and his legacy. That should come as no surprise: The nation’s longest-serving leader, Roosevelt presided over the New Deal and waged the successful World War II fight against global fascism. His New Deal laid the groundwork for the economic boom that made the United States the envy of the world in the postwar decades, and it provided the impetus for the civil rights and Great Society reforms of the 1960s. Roosevelt helped forge a coalition that made the Democratic Party dominant for almost half a century and left a lasting legacy, including programs that remain strikingly popular today, such as Social Security.

Yet for the past half a century, leading Democrats have let Republicans dictate the terms of our politics, expressing surprising reluctance to celebrate Roosevelt or the New Deal.

Recently, however, both have returned to American politics with a vengeance. Newly elected Democratic Rep. Alexandria Ocasio-Cortez (N.Y.) and dozens of other representatives have proposed a “Green New Deal.” Calling for a return to the progressive system introduced during the New Deal and World War II years, Ocasio-Cortez is also promoting a 70 percent marginal tax rate for the highest earners, a proposal other members of her party and some liberal commentators have endorsed. The call for what Sen. Elizabeth Warren (Mass.) describes as a “Second New Deal” marks the reversal of decades of Democrats distancing themselves from Roosevelt and, if this new trend continues, promises to reinvigorate the party and its agenda.

The “New Deal order” lasted roughly from Roosevelt’s election in 1932 to Ronald Reagan’s ascendance in 1980. This era presents a paradox. On the one hand, many, including Donald Trump, look back on it as a golden age. Yet beginning in the 1970s, the forces that helped produce a broad middle class and relative income equality have been under assault — from both parties.

Conservatives had always been suspicious of the New Deal, with its corporate regulation, robust spending on public goods such as education and state support for an expanded labor movement. No surprises there. What changed is that as these programs came under critical scrutiny, many Democrats, rather than robustly defending Roosevelt’s legacy, piled on. In 1985, then-Sen. Al Gore described the “New Deal formula” not as a model to be emulated but as an out-of-date paradigm of overreliance on “centralized government solution[s]” to be avoided.

There were understandable reasons for this shift from reverence for the New Deal to distancing from it. Economic growth slowed, inflation surged, globalization challenged American manufacturing dominance, states and municipalities endured fiscal crises, and white backlash against civil rights achievements frayed the Democrats’ once-formidable cross-race coalition.

Then, in 1980, Reagan won a sweeping victory with a platform promising to overturn the New Deal. His overwhelming reelection in 1984 seemed to mark a popular embrace of policies that were the very opposite of Roosevelt’s: opposition to nonmilitary government spending, anti-union animus, unregulated markets and, above all, denigration of government itself as the “problem” rather than the “solution” to the nation’s problems, as Reagan famously put it in his first inaugural address.

Democrats acknowledged other causes of political weakness, including the disastrous Vietnam War, which brought down Lyndon Johnson’s administration and the “Great Society” that he promoted as a successor to the New Deal. But many Democrats, like their conservative opponents, focused on flaws in the New Deal paradigm, which became a symbol of lumbering big government, prone to overregulation and in the pocket of organized labor, unsuited for the globalized world.

Following the 1980 proclamation of Sen. Daniel Patrick Moynihan (D-N.Y.) that the Republicans had become the “party of ideas,” many Democrats and liberals believed that they, by contrast, were stuck in the past, and that new realities had rendered New Deal liberalism moot. Yet this was never true. The supposedly fresh GOP “ideas” that Moynihan spoke of — that the federal government spent wastefully and was potentially “tyrannical” — were among the oldest chestnuts of the conservative critique of the New Deal. Still many Democrats, especially an influential group of reform politicians and pundits who called themselves “neoliberals,” believed that their party needed to reinvent itself to transcend what James Fallows, Jimmy Carter’s speechwriter, called “the tired formulas of left and right.”

The search for something beyond the New Deal often amounted to a rejection of its fundamental principles. Democrats helped shape the language of an “entitlements crisis,” built on the notion that the New Deal and Great Society programs were no longer affordable. For reform Democrats, new “ideas” meant finding a post-New Deal grounding to accommodate the new realities setting limits on social policy. But this acceptance allowed Republicans, in essence, to set the terms of debate. After all, it was Reagan whose policies ballooned the deficit and Republicans who routinely railed about government.

Even Democrats who wished to avoid adopting what operative Ted Van Dyk called in 1995 “a third-rate grab bag of conservative notions” often wound up promoting ideas that inadvertently advanced the Reagan Revolution. Believing that Democrats had to demonstrate their willingness “to discipline the welfare state,” Van Dyk thought it important for Democrats to disprove those who say “we lack the guts to reform” Social Security, Medicare and Medicaid.

This was the dilemma many Democrats felt after the collapse of the New Deal order: To prove their seriousness, they felt a need to reject, or at least modify, the achievements of the New Deal coalition.

In contrast, Republicans, now the widely recognized “ideas” party, doubled down on the anti-New Deal traditions that their conservative wing had long embraced. Whereas in the past they had been criticized for opposing the New Deal, in the 1980s and 1990s they became praised as innovators. Continuing to take the New Deal as their anti-model freed them to celebrate Roosevelt’s model of transformation, if not his ideology. Ironically, it was the Republican House speaker, Newt Gingrich (Ga.), not President Bill Clinton, his political enemy, who declared Roosevelt “the greatest President of the twentieth century.”

Recently however, we’ve seen signs that this may be changing and that the left may be reclaiming the mantle of its greatest accomplishments. Ocasio-Cortez celebrated both Abraham Lincoln and Roosevelt as “radicals who have changed this country.” In a 2015 speech at Georgetown University, Sen. Bernie Sanders (I-Vt.) invoked Roosevelt eight times, suggesting that New Deal liberalism provided a useful template for his vision of Democratic socialism (and far better branding).

It is too soon to say whether the Democratic Party as a whole will follow the lead of its left flank. But growing support for a Green New Deal, Medicare-for-all, progressive taxation and corporate regulation suggests that many members of the Democratic Party are once again embracing the Rooseveltian vision of activist government that promotes freedom, opportunity and justice for ordinary Americans. After half a century of consensus that the Age of Roosevelt was history, today’s Democrats are reclaiming the mantle of the party of ideas by reembracing the New Deal as a vision of positive governance.