Arizona voters will decide again in November whether to change the state’s constitution to define marriage as a union between one man and one woman.

A 16-4 vote by the state Senate on Friday night sends the gay marriage ban to the ballot. It had previously been approved by the House.

Arizona voters rejected a similar state constitutional amendment in 2006. That measure would have also stopped the state from recognizing civil unions of same-sex couples.

Arizona law already prohibits same-sex marriages. Supporters say this proposal would protect the sanctity of families by preventing judges from overturning the 1996 state law.

Sen. Paula Aboud of Tucson, who is openly gay, accused the amendment’s supporters of being “afraid of me and my relationship.”