Page "Supermajority" Paragraph 10

However, the United Nations Security Council does require a supermajority of the fixed membership on substantive matters ( procedural matters require a simple majority of those present and voting ).

According to Article 27 of the United Nations Charter, at least nine of the Security Council's 15 members ( i. e., a three-fifths supermajority ) must vote in favor of a draft resolution in order to achieve passage.

Specifying the fixed membership has the effect of making abstentions count as votes against — absences are not normal but would be treated the same way.