Democrats running for president in 2020 are faced with a choice when making their pitch to voters: make attacking President Trump a key part of their message or ignore him and focus on introducing themselves and their ideas.

On the one hand, criticizing Trump could help candidates convince primary voters that they’re able to defeat him, but depending on what shots they choose to take, they could risk alienating voters in the general election. So we wanted to see how the candidates tackled this choice by looking at one of the most direct ways they regularly communicate with voters — their emails.

Lindsey Cormack, who runs the DCinbox project, a public database of email newsletters sent by members of Congress, says emails, like tweets, can give us insight into how politicians try to brand themselves. “They don’t have to deal with editors at the paper. They don’t have to deal with booking an agent to be on a TV or radio program. They can really say anything they want.”

So to get a better sense of what the candidates told their followers about Trump, we subscribed to the mailing list of every candidate that FiveThirtyEight considers “major” and looked at all the emails they sent in the month prior to the first Democratic debate. (Though, for a variety of reasons — including email targeting practices, engagement testing techniques and the fact that we haven’t given money to any of these campaigns — we may not have received all the emails sent by all the campaigns. )

Overall, the candidates have taken very different approaches. Some candidates, like Sen. Elizabeth Warren, seem to be ignoring Trump almost entirely, while others, like former Vice President Joe Biden, are heavily peppering their emails with invocations of Trump. Even some lesser-known candidates like Montana Gov. Steve Bullock are going all in on Trump — every email we received from his campaign during this period contained a reference to the president.

Biden’s emails contained the second-most mentions of Trump. In total, we received 27 messages from his campaign that referenced the president by name. This strong focus on Trump seems aimed at portraying Biden as a strong general election candidate, which makes sense, as his perceived “electability” has been a central argument of his campaign.

In his emails, Biden has attacked Trump’s campaign tactics, his policy stances and his values. Biden has even sent an email that, rather than concentrating on his campaign, asked readers to sign a petition to “tell Donald Trump that welcoming foreign interference in our elections is unacceptable.” Even many of Biden’s fundraising emails are all about Trump, asking readers to “imagine the shock on Trump’s face” when they hit their fundraising goal and collect enough to “compete with Trump’s fortunes.”

While Biden mentions Trump often, his emails completely ignore the rest of the primary field — none of his messages mention another Democratic candidate by name. Another thing Biden never mentions? Impeachment.

And that’s a telling omission, because many other candidates have called for Trump’s impeachment and are renewing those calls in their emails. The move could help them in the primary election, as impeachment is popular among Democrats, but could prove risky in a general election because most polls find that more Americans oppose impeachment than support it.

In the month leading up to the first debate, Sen. Kamala Harris, former Cabinet secretary Julian Castro, Sen. Kirsten Gillibrand, Sen. Cory Booker, former Rep. Beto O’Rourke and former Gov. John Hickenlooper all sent at least one email entirely devoted to calling for Trump’s impeachment. O’Rourke, for example, sent a long email on May 30 explaining why he thought Trump should be impeached, and then a punchier one about two weeks later with “Donald Trump” as the subject line and “… should be impeached” as the only text in the body of the email, with a link to a petition.

While Warren was the first 2020 Democratic candidate to call for Trump’s impeachment — she publicly embraced that stance after the April release of special counsel Robert Mueller’s report on Russian interference in the 2016 election — we didn’t receive any emails from her campaign that mentioned the topic in the month before the first debate. Likewise, Sanders has also called for Trump’s impeachment, but didn’t send us any impeachment emails during the period we looked at.

Some candidates largely avoided talking about Trump at all in the month before the debate. For example, South Bend, Indiana, Mayor Pete Buttigieg only mentioned Trump in one email, when he called Trump’s tariffs on Mexican goods “politically-motivated gamesmanship.” Warren also was largely silent on Trump in this period. Of the 56 emails she sent us that month, only four mentioned Trump, and of those four, only one focused on him for the bulk of the message. That email explained, “Our campaign isn’t about Donald Trump. That’s because he’s just the symptom, not the cause, of the crises we face as a country.” And Rep. Tim Ryan, who sent us 78 emails — the most of any candidate — didn’t mention Trump even once, although he, too, has called for Trump’s impeachment.

Bullock, on the other hand, mentioned Trump in every single email, often as part of a formulaic reminder to subscribers that he is the only presidential candidate to have won statewide office in a state Trump won.

Candidates who have a harder time making an “electability” argument than Bullock varied widely in the tenor of their emails that mentioned Trump. New York City Mayor Bill de Blasio, for example, sent us fewer emails in the month leading up to the debate than most candidates, but he mentioned Trump in five of the seven emails he did send us. (And one the two that didn’t mention the president’s last name still used the hashtag #ConDon, which showed up in six of de Blasio’s emails and is meant to imply that Trump is a con man.) In many ways, De Blasio seemed to be trying to out-Trump Trump, aggressively attacking him and using name-calling tactics that the president is known for. In one email, for instance, he called Trump a “New York con man who’s just been made to smell his own BS” and referred to Rudy Giuliani, Trump’s lawyer, as Trump’s “lapdog,” whose insults were “even lamer than his boss’s.” But unlike de Blasio, most of the Democratic contenders seemed to have heeded former First Lady Michelle Obama’s advice to “go high” when their opponents “go low” and are trying to strike a different tone than the current president, rather than trying to outdo him.

So what does this tell us about how Democrats are crafting (or not crafting) their campaigns around Trump? Well, a few candidates, like de Blasio, Bullock and Biden, are at one extreme — mentioning Trump at practically every opportunity — and a few, like Ryan and Buttigieg, are firmly planted at the other extreme, remaining largely silent on Trump. But perhaps unsurprisingly, most candidates fall somewhere in between, striking a balance between talking about Trump and focusing on their own message. It’s early yet, though, and some candidates’ communication strategies might change as the primary progresses. Still, with so many Democrats running, the party will have collectively tried out many different avenues of attack before the general election. Ultimately, however, there will only be one Democratic nominee, and whoever that is, he or she will have a wide pool of pre-tested approaches to draw from.