Inside Twitter, dealing with Mr. Trump’s tweets — which are the equivalent of a presidential megaphone — was a fitful and uneven process. Some executives repeatedly urged Mr. Dorsey to take action on the inflammatory posts while others insisted he hold back, staying hands-off as the company had done for years…

Twitter is girding for a protracted battle with Mr. Trump. Some employees have locked down their social media accounts and deleted their professional affiliation to avoid being harassed. Executives, holed up at home, are meeting virtually to discuss next steps while also handling a surge of misinformation related to the pandemic…

In 2018, two of the president’s tweets stood out to Twitter officials. In one, Mr. Trump discussed launching nuclear weapons at North Korea, which some employees believed violated company policy against violent threats. In the other, he called a former aide, Omarosa Manigault Newman, “a crazed, crying lowlife” and “that dog.”

At the time, Twitter had rules against harassing messages like the tweet about Ms. Manigault Newman, but left the tweet up.