Novus Ordo Watch

Novus Ordo Watch is a sedevacantist website and social-media presence; it holds that the post–Vatican II claimants to the papacy are not true popes, and a critic summarises its claims as including that the Novus Ordo Mass is Protestantised and that Vatican II embraced modernism (Sacerdotus). Its Substack profile describes it as a sedevacantist non-profit organisation registered in Ohio (Substack). The site publishes long-form polemics and replies to critics, for example a 2015 essay rejecting the charge that sedevacantism amounts to Protestant private judgment, a 2022 reply to Crisis editor Eric Sammons on the "spiritual dangers" of sedevacantism, and a response to Fr. Chazal on the SSPX and sedevacantism (Novus Ordo Watch; Novus Ordo Watch; Novus Ordo Watch).

It also produces TRADCAST, which podcast directories describe as a traditional Catholic podcast produced by NovusOrdoWatch.org. One 2021 episode carries a lecture, "Eclipse of the Church: The Case for Sedevacantism", delivered by Mario Derksen at a Fatima conference hosted by the Congregation of Mary Immaculate Queen (CMRI) in Spokane, Washington, on 8 October 2021 (Apple Podcasts; Player FM). Derksen is publicly associated with the site: a Catholic Family Podcast episode is titled "A Chat with Novus Ordo Watch - AKA Mario Derksen" (Catholic Family Podcast), and The Remnant has described him as running the site (The Remnant).

In April 2025 UnHerd, in an essay on sedevacantism, called Novus Ordo Watch a "meme-posting page" with more than 25,000 followers on X and 13,000 on Facebook, and estimated that there are at most 30,000 sedevacantists worldwide (UnHerd). Its arguments are contested by traditionalists who recognise the post-conciliar popes, including the True or False Pope website; its authors Siscoe and Salza have publicly debated Derksen and Fr. Anthony Cekada (True or False Pope; The Remnant). See Sedevacantism and Validity of the Novus Ordo.