This week's Holy Smoke examines the fragmentation of American Catholicism following the election of pro-choice Catholic Joe Biden. It focuses on the strangest current of thought among the many conservative Catholics calling for an urgent change of approach in order to confront what promises to be an authoritarian liberal administration.

It's called integralism, a label previously attached to distinctly un-American European Catholic reactionaries such as Action française and General Franco's Falangists. In its US incarnation it's less nationalist but in some ways equally extreme. Its proponents want to turn the United States into a nation in which, in the long run, only Catholics will be full citizens eligible to hold office. This new integralism is a medieval fantasy built around the teachings of St Thomas Aquinas. It has been labelled 'clerico-fascist' by its critics – and also, more convincingly to my mind, 'Catholic Sharia'. No one is going to vote for it, of course, but as you'll hear in this episode it could well have an impact on US politics.