Twitter CEO Jack Dorsey on Wednesday discussed the platform’s decision to permanently suspend President Trump’s account last week for violating it policies.

In a lengthy Twitter thread on Wednesday, Dorsey said the company “faced an extraordinary and untenable circumstance, forcing us to focus all of our actions on public safety. Offline harm as a result of online speech is demonstrably real, and what drives our policy and enforcement above all.”

Dorsey recognized, however, that having to ban an account has “real and significant ramifications,” adding that doing so is a “failure of ours ultimately to promote healthy conversation. And a time for us to reflect on our operations and the environment around us.”