Since the 2016 election, there has been one question on the minds of everyone in the Democratic Party, “How do we beat Donald Trump?”

Everyone has their own theory and thoughts on how Democrats can take back the White House in 2020, but the truth of the matter is, to beat Trump, Democrats are going to have to become more like Trump. Many Democrats may say that sounds crazy and confusing. But if the Democrats look back at why Trump won in the first place, they could get a pretty good idea of how Democrats can take him down in 2020.

Now why did Trump win in 2016? How did a guy who ran a campaign that was bogged in controversy and backlash at every turn pull off a stunning victory over a political powerhouse like Hillary Clinton? Well it’s pretty simple, he sensed people were struggling and frustrated and ran a campaign based upon that. Many voters felt like Trump tapped into the heart of what they were hoping to hear from their elected officials. In other words, he ran a very populist campaign that was focused on the plight of the American people.

Trump ran a campaign that was fervently anti-free trade. He called the North American Free Trade Agreement “The worst trade deal ever signed,” and promised to “either renegotiate it, or we will break it,” if elected president. Jeff Faux of The Economic Policy Institute says, “NAFTA undercut the bargaining power of American workers, which had driven the expansion of the middle class since the end of World War II. The result has been 20 years of stagnant wages and the upward redistribution of income, wealth and political power.”

Trump called the Trans-Pacific Partnership “an attack on America’s business” and said the TPP would “squeeze our manufacturing sector” and lead to a rise in unemployment.

To put it simply, NAFTA, the TPP and other trade deals have been terrible for workers in the U.S.

States that were Democratic strongholds during the Obama presidency such as Wisconsin, Michigan, Iowa, Ohio and Pennsylvania (a combined 70 electoral votes) went to Trump in 2016 because he was able to win over a significant number of Obama voters. A study by the Democracy Fund found that 9.2% of Obama voters voted for Trump in 2016. These Obama voters didn’t go to Trump because the voters there are racists or misogynists or Islamophobes. They voted for Trump because he promised he would save their jobs and their livelihoods.

His stance on free trade was enough to convince many Obama voters to vote for Trump in 2016. They made a conscious decision to look past some of his racially divisive and misogynistic comments made during the campaign because they believed Trump could save their livelihoods and put more money back into their pockets.

However, many Americans now know that much of Trump’s rhetoric on the campaign trail was simply a farce when you look at what he’s done in his 2 1/2 years in office. Trump promised to bring back many of the jobs that were lost under NAFTA and other various free trade deals. Instead, some 93,000 jobs were outsourced in Trump’s first year alone. Trump said he would either renegotiate or “break” NAFTA, of which he chose the former. The United States-Mexico-Canada Agreement, as Trump’s NAFTA renegotiation is officially known, is projected to boost the U.S. economy by less than 0.4%, according to a report by economists from the United States International Trade Commission. In an article for Quartz, Gwyn Guilford said, “The USMCA will cause the American economy to shrink a wee bit…by about $23 billion. It will also drive down wages a tad and put nearly 54,000 people out of work. In other words, American companies, workers, and consumers as a whole will be slightly better off if the USMCA doesn’t pass.”

Trump issued an executive order that removed the United States from the TPP during his first week in office, but he recently stated he would begin to look into rejoining the agreement if it could also be renegotiated, but many foreign officials say it is too late for the agreement to be negotiated.

So, to be frank, Trump has utterly failed to uphold many of the promises he made on the campaign trail that got him elected in the first place.

These policies that Trump failed to deliver on offer the Democrats a perfect opportunity to take him down in 2020 if they can find a candidate who shares some of Trump’s policy on these issues without abandoning their core principles such as universal health care, climate reform, immigration reform and a liberal approach to social issues.

2020 Democratic Presidential candidates, such as Sen. Bernie Sanders and Sen. Elizabeth Warren, have had similar stances to Trump on free trade, while simultaneously being seen as two of the most socially progressive politicians in the country. Warren called Trump’s reconsideration into rejoining the TPP a “ridiculous reversal” and a “slap in the face” to workers. Officials in Sanders’ office tweeted that reentering the deal “would be a betrayal of American workers.”

If the Democrats can find a candidate who is an unapologetic champion for the core principles that have become the platform of the party, then they will have a strong candidate. However, if they can find a candidate who champions these principles along with some of the same populist policies that appeal to American workers in the Rust Belt and that Trump used to win over so many previously Democratic voters in 2016, then they have a candidate who may be unbeatable.