Mike Blake / Reuters

Michael Avenatti was never going to be president. The Avenatti boomlet, which began in August, lasted for a little less than three months, until the attorney officially took himself out of the running on Tuesday, citing concerns about his family.

Avenatti made a name for himself representing the adult-film actress Stormy Daniels, whom President Donald Trump paid during the closing months of the 2016 campaign to keep quiet about an alleged affair a few years earlier. Avenatti has a telegenic presence, and he satisfied a need among angry liberals for a champion who was as nasty to the president as the president is to, well, almost everyone.

“I believe our party must fight fire with fire,” Avenatti told a crowd at a Democratic event in Iowa in August. “When they go low, I say we hit harder.”

That doesn’t mean, however, that Avenatti, who has never held elected office, made a good or appealing presidential candidate. Avenatti was arrested on domestic-violence charges in November, and his declaration that the next Democratic presidential nominee “better be a white male” raised eyebrows, to say the least. Although numerous pundits speculated that Avenatti would become the Democrats’ version of Trump, this assessment misunderstands the nature of the two major parties. Trump emerged from a crowded GOP presidential field because of his expressions of public loathing against demographic groups that conservatives fear and his promises to use the power of the state against them. But the Democratic Party is simply too reliant on a base that is both ideologically and ethnically diverse to support a candidate who is a negative image of Trump. It is not that Democrats are more virtuous. It is that the Democratic Party’s viability rests on too many different types of people to run campaigns that rely entirely on promises to crush the other side.

Although the Republican Party has grown more conservative in recent years and the Democratic Party has grown more liberal, the Democrats rely far more on conservative voters than the GOP does on liberal voters. According to Pew, only 4 percent of Republicans identify as liberal, 27 percent as moderate, and 68 percent as conservative. By contrast, 46 percent of Democrats identify as liberal—a large increase from 2000, when that figure was only 28 percent, but far less than the percentage of Republicans who identify as conservatives. Moderates account for 37 percent of Democratic voters, and conservatives 15 percent.

That asymmetry means that Democrats are forced to appeal to groups that lean Republican in order to win. This sometimes leads to comically awkward pandering—think of former Vermont Governor Howard Dean declaring that he wants to be president for the guy who has a Confederate flag on his truck, or Hillary Clinton needling Barack Obama over his lack of support from “hardworking Americans, white Americans.” When a Democrat with statewide or national ambitions does antagonize one of these conservative-leaning groups, whether it’s Obama describing Clinton primary voters as people who “cling to guns and religion” or Clinton saying that half of Trump supporters are racist, it is a potentially campaign-ending gaffe.

Contrast that with a Republican senator like Ted Cruz, who accused his Democratic rival of trying to make Texas like California, “right down to tofu and silicon and dyed hair.” When Democrats trash Republican-leaning constituencies, it’s a political catastrophe. When Republicans trash Democratic-leaning constituencies, it’s Tuesday.

A premature autopsy of Beto O’Rourke’s run against Cruz, in which he came within three points of unseating the incumbent, argued that “Democrats win in red states … not by painting bold contrasts but by minimizing differences.” This was a bit of a strange assessment—O’Rourke did far better than a number of more conservative Democrats running in other states, who got wiped out; he helped Democrats overwhelm Republicans in dozens of down-ballot races; and he came closer than any Democrat in a generation to winning a statewide race in Texas. But it underscores the point that unlike Republicans, Democrats cannot afford to alienate huge swaths of the population and still expect to win big races. O’Rourke came close not because he trashed prospective Cruz voters or even Cruz himself, but because he offered the kind of unifying, starry-eyed liberal rhetoric that has proved successful for certain Democrats in the past.

This asymmetry isn’t just ideological. Forty-three percent of white voters are Democrats, compared with 51 percent of white voters who lean GOP. That means white voters remain an essential part of the Democratic coalition—which is precisely why Fox News and other conservative media outlets serve so much culture-war red meat, fomenting white panic about diversity, telling their audiences that Democrats are racist against white people or want to take away Christmas. But unlike the Republican Party, Democrats must also draw support from black, Latino, and Asian voters—meaning they can’t afford to antagonize them, and must be responsive to their interests.

Republicans are almost entirely reliant on white voters—which is why generalizations about racial and religious minorities meet with so little pushback within the party. There is simply no constituency willing to hold Republican politicians accountable for such remarks—on the contrary, most of the party either sees both the generalizations and the discriminatory policy approaches that emerge from them as admirable or remains in denial about what is happening.

The divergence is clear even in the respective parties’ choice of standard-bearers. Obama’s rise to political stardom came after a speech in which he declared that “there’s not a black America and white America and Latino America and Asian America; there’s the United States of America.” And Trump’s came from his strategic deployment of the slander that the first black president was born abroad and was therefore illegitimate.

These distinctions mean that Democrats cannot afford to attack Americans who have only a high-school education the way that Republicans wage culture war against academia. Democrats cannot dismiss seniors the way Republicans condescend to young voters. Democrats cannot represent white men as a national-security threat after a terrorist attack the way Republicans can call to ban members of an entire religion from entering the country. Democrats must take care to not alienate police in the aftermath of unjustified police shootings, while Republicans can assassinate the character of entire communities. Democrats seeking higher office cannot hate the people who vote Republican the way that Republicans can hate people who vote for Democrats, not because Democrats are inherently better people but because they need the votes. And that means that without a fundamental change in the constituencies of both parties, there can never be a Democratic Trump.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.