Sen. Bernie Sanders (I-Vt.) called on surrogates representing his 2020 presidential campaign in the media to “respectfully engage” his opponents in the Democratic presidential primary, encouraging them to focus on policies rather than personalities.

In the Saturday email to over 100 campaign surrogates obtained by HuffPost, Sanders also preemptively admonished supporters against “bullying and harassment of any kind.”

“As we engage with our opponents in the Democratic primary, we will forcefully present our views and defend ourselves against misrepresentations,” he wrote. “But, let us do our very best to engage respectfully with our Democratic opponents ― talking about the issues we are fighting for, not about personalities or past grievances. I want to be clear that I condemn bullying and harassment of any kind and in any space.”

Sanders’ missive is an early effort to short-circuit ad hominem attacks or bullying that is undertaken in his name.

During the 2016 presidential campaign, Sanders and his supporters endured criticism from backers of Hillary Clinton for the online vitriol they alleged was directed at them by some of his partisans. Some of Sanders critics renewed calls for him to exercise greater control over his supporters since he kicked off his 2020 bid last Tuesday.

Sanders in his Saturday email said employing divisive rhetoric would be particularly counter-productive given his campaign’s bottom-line goal of unseating President Donald Trump, who is notorious for his bullying and bigotry.

“The President we are running against is a pathological liar, a racist, a xenophobe, a sexist, a bully and a religious bigot. His goal is to win political points by dividing up the American people,” he wrote. “That is why we need to do exactly the opposite ― brings our people together. Men and women, black and white, Latino, Native American, Asian American, gay and straight, young and old, native-born and immigrant.”

Sanders argued that personalizing the already crowded Democratic primary would undermine his progressive message, making it harder to unite the party against Trump in the general election.

“Our number one priority is defeating Donald Trump. To do so, we will ultimately have to unite with those who today are our opponents for the Democratic nomination,” he added.

Here is the complete text of the email: