After temporarily suspending President Trump's account earlier this week, Twitter has announced they have permanently banned the account "due to the risk of further incitement of violence."
They announced the ban in a series of tweets below:
However, we made it clear going back years that these accounts are not above our rules and cannot use Twitter to incite violence. We will continue to be transparent around our policies and their enforcement.— Twitter Safety (@TwitterSafety) January 8, 2021
Twitter says that numerous factors went into their decision to ban President Trump, including incitement of violence. Twitter says that plans for future armed protests have already begun circling on and off Twitter, "including a proposed secondary attack on the US Capitol and state capitol buildings on January 17, 2021."
You can read Twitter's blog about permanently banning President Trump's account here.