Sen. Elizabeth Warren (D-Mass.) at an event in Des Moines this past weekend. (Brian Snyder/Reuters)
Opinion writer

While other potential presidential candidates are still huddling with their families to decide whether they want to run (at least that’s what they say), Sen. Elizabeth Warren (D-Mass.) has gotten a head start on the field by announcing the formation of her exploratory committee and heading to Iowa for a much-covered round of appearances. You can bet those other candidates are watching closely, especially because Warren has already defined the message we’re likely to hear in one form or another from every Democrat:

Massachusetts Sen. Elizabeth Warren is introducing herself to influential Iowa Democrats by telling her personal story of economic opportunity, trying to lay claim in the emerging 2020 presidential field as a champion for a middle class she says is withering under President Donald Trump.

On her first full day as a Democratic presidential prospect in the kickoff caucus state, Warren repeatedly argued that opportunities like hers have vanished because wealthy interests have bent policy makers in Washington to their will.

“They work for the rich and the powerful and not the rest of us. It’s throughout the system,” Warren said, igniting cheers from more than 500 in a downtown event hall Saturday evening. “This is corruption, pure and simple. It is corruption and it is eating away at our democracy and every fiber of our lives.”

Warren has the advantage of having framed politics in this way since before she first ran for office. But the reason it will likely be the focus of so many of the candidates in 2020 is that President Trump has made it the natural theme of the opposition against him. Furthermore, if Democrats are looking for a way to appeal to working people, this is the way to do it, not by trying to find a type of candidate whom you think will embody it. Every time Democrats make the argument, it works.

Warren weaves that story into her biography, recounting her family’s financial struggles when she was young. But any candidate can make the same argument, especially now. And you could not possibly have imagined an administration that has made it easier to hammer home the theme of a system built to enrich the rich and empower the powerful than Trump’s. His greatest policy achievement is an unpopular tax cut that primarily benefited corporations and the wealthy; he stocked his Cabinet with millionaires and billionaires; and he has made clear that he sees the presidency as a vehicle for personal enrichment. Right now, the acting secretary of defense is a former defense contractor executive, the acting EPA administrator is a former coal lobbyist, and the acting secretary of the interior is a former oil lobbyist. No one can reasonably dispute that Washington has become profoundly more corrupt under Trump.

Some have argued that if Hillary Clinton had argued more forcefully in 2016 that a President Trump would be an advocate for the wealthy, she might have won. While she did say that, it was subsidiary to her argument that Trump was an abhorrent human being who should not be allowed within a mile of the Oval Office, which seemed reasonable at the time. After all, how could people vote for a con artist who was on tape bragging about his ability to sexually assault women with impunity? But in 2020, we will no longer have to wonder about what kind of president Trump would turn out to be.

And while Trump talked about the system being “rigged,” the difference between what he said in 2016 and what Warren says now is that he never identified the villains. She does, talking about powerful corporations but especially about Wall Street, which somehow managed to destroy the U.S. economy, get bailed out by taxpayers, evade any accountability, and emerge making higher profits than ever. Trump had villains, of course — immigrants, mostly — but when he talked about how the system was rigged, he became vague. After all, he’s a Republican, so he wasn’t going to target the wealthy or the corporations who have economic and political power. He might say he knew how the system operates because he gave money to politicians who then did his bidding, but he didn’t propose any concrete changes to law to make that less likely in the future.

And now, Trump’s 2016 arguments can and will be used against him. Democrats seem to be coming to a collective realization that, while they can propose specific economic policies like raising the minimum wage and guaranteeing family leave, they also need to put them together to tell a broader story about what’s wrong in America — as well as why Trump is making things worse. Their economic message, furthermore, fits right in with their argument about political corruption and their proposals to reform voting rights and campaign finance.

In a perfect world, candidates wouldn’t need a “message” at all, because campaigns would be substantive discussions about a range of problems, and all the fancy marketing would be unnecessary. That is not the world we live in. In this world, a candidate has to sum up his or her entire candidacy in a short, easy-to-understand idea. The best messages tell the public what the problem is, what the solution is, and why that person is the one who can bring us from where we are now to where we need to go. “Make America Great Again” did that — it said that we had fallen from our prior glory and Donald Trump could rewind history and return us to a simpler time when things made sense and you didn’t have to tolerate people who don’t look or sound like you. For millions, it was extraordinarily compelling.

And when Trump said the system was rigged, he was met with nods of agreement from people whose lives were affected by wage stagnation, high insurance costs, the decline of secure jobs, and all that comes with ever-increasing inequality. He can’t make the same argument to them again. But Democrats can.