Jus exclusivae

Jus exclusivae Latin for "right of exclusion"; sometimes called the papal veto was the adjustment claimed by several Catholic monarchs of Europe to veto a candidate for the papacy. Although never formally recognized by the Catholic Church, the French monarch, the Spanish monarch, and the Holy Roman Emperor which later became the Emperor of Austria claimed this modification at various times, creating known to a papal conclave, through a crown-cardinal, that the monarch deemed a particular candidate for the papacy objectionable.

Right asserted since 1644

At the 1846 Papal conclave, Austrian Chancellor Klemens von Metternich confided Austria's veto of Cardinal Giovanni Maria Mastai-Ferretti to Cardinal Carlo Gaetano Gaisruck, Archbishop of Milan, who arrived too late. Mastai-Ferretti would reign as Pius IX for over thirty-one years.