Sedevacantism, American Catholicism's only homegrown "new religious movement" (NRM), argues that the Catholic Church has sunk into heresy at the hands of false popes. It sits at the extremes of two growing phenomena: Traditionalist Catholicism and Independent Catholicism. The only Roman Catholic bishop ever to espouse Sedevacantism was Archbishop Pierre Martin Ngô-dinh-Thục -- but who was he?

ARCHBISHOP THỤC, Godfather of Vietnam's notorious ruling clan, key CIA contact, and apologist for a brutal, failing regime. But Thục escaped, leaving behind a mysterious fortune, secret deals, abuse cover-ups, and the Vietnam War. In exile, Thục helped launch the fanatical Palmarian cult (which later canonized Franco and Hitler), inspired assorted renegades, and reemerged as the icon of a new hardline movement called Sedevacantism.

SEDE VACANTE: The Life and Legacy of Archbishop Thục painstakingly reconstructs this remarkable story: from French Indochina to the Japanese occupation; from the Communist revolution to the doomed US-backed puppet regime; from Thục's exile to his role in Vatican II. Sede Vacante investigates the origins of the secretive Palmarian cult and analyzes the theological, sacramental, and canonical issues arising from all of Thục's exploits; it explains why, now more than ever, Catholics and non-Catholics alike should be aware of Sedevacantism.