Editor's Note: (Julian Zelizer is a history and public affairs professor at Princeton University, editor of "The Presidency of Barack Obama: A First Historical Assessment" and co-host of the "Politics & Polls" podcast. Follow him on Twitter: @julianzelizer. The opinions expressed in this commentary are those of the author. View more opinion articles on CNN.)
(CNN) On the first day of her unofficial presidential campaign, Sen. Elizabeth Warren showed exactly why President Trump is such a powerful political opponent. Unlike most other presidents in recent decades, he has the capacity to set the terms of debate and to bring his adversaries into conversations they never intended to have.
Warren released a video that is in many ways extremely compelling. Drawing on Jimmy Carter's famous biographical campaign film in 1976 that helped to distinguish him based on his upbringing, Warren reveals to Americans how she is a genuine product of the "ragged edge of the middle class" that struggles every day to make ends meet in middle America.
If the question of the 2020 presidential campaign ends up coming down to which candidate has a better understanding for the hopes, struggles and pains of average Americans, the video effectively suggests, it would be Warren as opposed to a President whose wealth was inherited and whose financial success came from shady tax practices. In the video, Warren also hits hard at the kind of racism that has influenced many of Trump's attacks, standing as a defender for Native Americans who have become the victims of the "blood sport" of politics.
But the video also plays into the President's hands by literally being framed around Trump. It starts with President Trump throwing out his "Pocahontas" insult to adoring crowds. After turning back to her family background and struggles for a bit, the video returns to Trump's suggestion that she lied about her heritage to advance her academic career.
We learn about a DNA test that proves there are Native Americans in her family background, however distant. Warren tries to make the case based on expertise. Trump offers insults; Warren, a former Harvard University professor, offers data.
The dangers of this strategy for Democrats became clear within hours. Instantly, the news cycle turned to debates about the DNA test. In predictable fashion, the rest of her message quickly faded away in the frenzy of news analysis. The upshot: Warren, one of the most intelligent and capable senators to have served in the upper chamber for decades, finds herself trapped in a Trumpian debate that has little relevance to the nation's future. Trump mastered this strategy years ago when he was a key figure in the birther movement that consumed much too much of the nation's energy on the phony issue of whether President Obama was really a US citizen.
As a candidate and President, Trump has continually done this to his opponents. During the 2016 primaries, Republicans were forced to contend with the nicknames Trump gave them on the campaign trail. Hillary Clinton was swamped in a campaign that revolved around her emails, a minor issue that Trump exploited.
Every opponent since he took office has been forced to contend with the conversation topics he put forth: for example, the Democratic candidates in 2018 who suddenly find themselves using the final weeks of a historic campaign to talk about whether they are an unruly extremist mob.
Moreover, Warren's response is based on an assumption that evidence matters in these battles with Trump. President Trump has minimal interest in what the data says about almost any issue. He believes his "gut" is usually right and is usually able to find some fringe voice ("people say") to support his most outlandish claims.
Trump's political method is to repeat his messages endlessly regardless of what the facts show. Once he starts a conversation, he understands they are difficult to control and there is a 24-hour, instantaneous news cycle where information reaches the public before it is checked and verified.
Even after Obama produced his birth certificate, which Trump pointed to as a victory, he didn't stop from asking questions about the former president's origins. On a wide range of issues, from "voter fraud" to climate change, President Trump is never influenced by the data. When his opponents engage his debates by producing mountains of evidence to dispute his claims, he only uses their response to fuel the conversation in a way that does not serve their purpose.
In this case, Warren's response has not been helped by the fact that some liberals as well as a Native American organization have taken issue with the way she wants to claim this as part of her identity. By entering the debate, she unnecessarily opened herself up to these challenges.
Warren certainly has the capacity to shape a campaign around vital issues that she has played a major role in promoting — middle class insecurity, income inequality, consumer protection, gender equity and more. There is no need for her to relegate herself to what the President wants to discuss — or, more importantly, tweet about.
Any Democrat or Republican who hopes to seriously challenge President Trump in 2020 will have to be capable and willing to shape the national debate on their own terms rather than on those of President Trump. If they don't, President Trump, a master storyteller, can twist his opponents into knots as they dive deeper and deeper into a political abyss.