Catechism of the Catholic Church §2243 — excerpt
Armed resistance to oppression by political authority is not legitimate, unless all the following conditions are met: 1) there is certain, grave, and prolonged violation of fundamental rights; 2) all other means of redress have been exhausted; 3) such resistance will not provoke worse disorders;…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.