Pius XII had been narrowly elected pope before seeking an additional ballot to demonstrate wider support, and he knew that a very close ballot in the
1914 conclave had raised the question of the impact of a cardinal's vote for himself. Pius XII promulgated the
apostolic constitution Vacantis Apostolicae Sedis on 8 December 1945, more than six years after his election. He made only two significant changes in conclave procedures, otherwise following those established by
Pius X on 25 December 1904 with the constitution
Vacante Sede Apostolica. Firstly, he increased the majority required for election from two-thirds of those voting to two-thirds
plus one, so that an elector's vote for himself would be insufficient to produce a two-thirds majority. He also eliminated the rule against voting for oneself, which the two-thirds-plus-one rule obviated. It holds, though, that if one had an exact two-thirds majority, not counting one's own vote, a cardinal could cast the deciding vote for himself. Secondly, from 1621 to 1945, the ballots used to be signed with folded over flaps to conceal the signatures of the electors. Pius XII removed the signature portion of the new form of ballot, so that a completely secret ballot is now cast by each elector with the oath taken at the same moment, now being anonymous. All this is clearly stated in the apostolic constitution
Vacantis Apostolicae Sedis promulgated by Pius XII on 8 December 1945. ==See also==