Roman Catholic bishops for Arizona endorsed a proposed state constitutional amendment intended to prohibit same-sex marriages on Thursday.
The measure will appear on the November ballot as Proposition 102.
If approved, it would define a valid marriage in Arizona as only a union of one man and one woman.
Bishops Thomas J. Olmstead of Phoenix and Gerald F. Kicanas of Tucson say they base their support on their church's teaching on the sanctity of marriage as a lifelong union of a man and a woman.
Proposition 102 opponents say the amendment is not needed because state law already prohibits same-sex marriage.
Arizona voters rejected a broader marriage amendment in 2006.
