Non Expedit (Latin for "It is not expedient") were the words with which the Holy See enjoined upon Italian Catholics the policy of boycott from the polls in parliamentary elections.
The papal policy was adopted after the promulgation of the Constitution of the Kingdom of Italy (1861), and the introduction of laws relating to the Catholic Church and, especially, to the religious orders (1865–66).
Pius IX declared in an audience of 11 October 1874 that the principal motive of the Non expedit decree was that the oath taken by deputies might be interpreted as an approval of the 'spoliation of the Holy See'.
[1] The decree did not meet with universal approval; moderates accused the Vatican of failing in its duty to society and to the newly unified country.
[1] Later Pius X, by his encyclical "Il fermo proposito" (11 June 1905) modified the Non Expedit, declaring that, when there was question of preventing the election of a "subversive" candidate, the bishops could ask for a suspension of the rule, and invite Catholics to hold themselves in readiness to go to the polls.