Julian Zelizer is a history and public affairs professor at Princeton University and the editor of " The Presidency of Barack Obama: A First Historical Assessment ." He's also the co-host of the "Politics & Polls" podcast. Follow him on Twitter: @julianzelizer . The opinions expressed in this commentary are his own.

(CNN) The big myth about the 2016 presidential election was that economic suffering drove most of Donald Trump's "base" directly into his hands in states such as Wisconsin, Pennsylvania, and Michigan. The story goes that while Democrats were tied in knots about identity politics, Trump's attacks on China, free trade and open-ended immigration appealed to struggling workers who believed he could bring back their jobs.

The problem with the narrative is that we keep learning it is not true.

Some Democrats have responded to the widely circulated misconception about why Clinton lost by insisting that the party needs to move away from identity politics -- issues revolving around gender equality and racial justice -- and focus in on economic issues.

Instead, Democrats should be basing their 2020 election strategy on what is actually true.

A just-published study in the Proceedings of the National Academy of Sciences by the political scientist Diana Mutz found that white, Christian, male voters were attracted to Trump out of fear that their social status keeps dwindling. It was, in fact, Trump who was focused on identity politics, not simply the Democrats.

Mutz's research found that members of Trump's base believed they faced more discrimination as white males than most other groups, such as Muslims. "For the first time since Europeans arrived in this country, white Americans are being told that they will soon be a minority race," she writes.

JUST WATCHED Sources: Allies telling Trump his base thinks he's softening on immigration Replay More Videos ... MUST WATCH Sources: Allies telling Trump his base thinks he's softening on immigration 04:13

To play off of Bill Clinton's 1992 famous campaign slogan, "It's the economy, Stupid," we might say: "It's the culture, Stupid."

Mutz's research offers a window into understanding why President Trump can promote a Reaganesque economic agenda that is so clearly at odds with his campaign promises.

While the President keeps talking about the common man and woman, most of his economic policies, such as his tax overhaul or financial deregulations, have aimed to provide relief to corporations, investors, and families in the upper income brackets. But it is key to understand that his legislative actions are happening simultaneously with his continued rhetoric -- attacks on immigrants, civil rights, gender equality, and anyone who dares to stand up for the ideas that he likes to deride as "political correctness" -- that secured the support of his base to begin with.

JUST WATCHED Trump's female base holds despite allegations Replay More Videos ... MUST WATCH Trump's female base holds despite allegations 02:56

So, although these attacks are sometimes seen as a "distraction," they are the main show, as Mutz's research demonstrates -- and they seem to be working. The nation is in the middle of a battle over what this country is about. Trump's attacks on immigrants and other groups seem to sit well with white male voters who fear that other segments of society are gradually displacing them.

And they still believe Trump is the only politician in Washington who truly understands the way their communities are suffering.

Democrats certainly need to pay more attention to economic issues. And historically the party has implemented polices -- which could now provide an alternative approach to appealing to anxious white, Christian men -- that have done so.

During the 1930s and early 1940s, President Franklin Roosevelt provided hard-working Americans some of the economic security they desired. FDR launched massive public works programs that created jobs for those who were unemployed, and he erected social safety-net programs -- like unemployment insurance and Social Security -- that protected working Americans from the vicissitudes of the market.

In the 1960s, Lyndon Johnson launched a "War on Poverty" that aimed to provide struggling Americans, white and black, with the tools they needed to become economically self-sufficient. Those tools also included health care programs, like Medicare and Medicaid, to ensure that elderly Americans could receive care without facing economic ruin.

Johnson and the Democratic Congress poured money into secondary and higher education to give working families an opportunity to advance their status.

But this kind of economic liberalism today might only go so far in winning over Trump's supporters. So, Democrats should be extremely wary about jettisoning the core social and cultural principles -- civil rights and gender equity -- that have animated their own base since the civil rights struggles of the 1960s.

Studies suggest that some of Trump's voters will not change their minds in response to any kind of economic policies. The only way for Democrats to win those voters over would be to turn their backs on core constituencies, like college-educated, working women, African-Americans, and immigrants, who have been vital to the party for decades.

Join us on Twitter and Facebook

So, rather than trying to appease the cultural anxieties of white male voters, Democrats should instead focus on offering them economic solutions to their challenges, such as pushing for a robust infrastructure program (polling showed that 53% of white males in states won by Hillary Clinton support an infrastructure initiative), while energizing, organizing, and mobilizing the millions of Americans who were part of the coalition that Barack Obama successfully wove together in 2008 and 2012.

It was a coalition that understood that the diversity of this country is its strength, not its weakness. Ultimately, the goal for Democrats should be to convince Trump's base that this is the only viable future for the democracy.

They might remember Hubert Humphrey, who told "States' Rights" Democrats at the 1948 party convention: "To those who say that this civil-rights program is an infringement on states' rights, I say this: The time has arrived in America for the Democratic Party to get out of the shadow of states' rights and to walk forthrightly into the bright sunshine of human rights."

In the short-term, Humphrey took a lot of heat for making that speech, which cost Democrats Southern votes. But in the long-run, he was on the right side of history.