Opponents of gay marriage scored a state-referendum sweep Tuesday, bringing some solace to social conservatives and anger and sorrow to gay rights activists.

Voters in Florida, Arizona and California approved state amendments that ban such unions. California had just recently granted same-sex couples the right to marry. Thirty states nationwide now specifically define marriage as between a man and a woman in their constitutions.

The Florida Marriage Protection Amendment, which defines marriage as a union between a man and a woman, was supported by more than 62 percent of voters statewide -- surpassing the 60 percent threshold required for ratification.

Supporters of Florida's Amendment 2 -- mostly conservatives and Christian groups -- argued it was needed to protect the ''traditional'' institution of marriage and families by promoting homes with a mom and a dad, not two moms or two dads.

''This was not about being against anyone," said John Stemberger, president and general counsel of the Florida Family Policy Council, which led the campaign to pass Amendment 2. "We're talking about a universal human social institution. It is undeniable how important that is."

While supporters said the amendment's only purpose was to define marriage as a union between a man and a woman and that it would not infringe on the rights of any Floridian, opponents disagreed.

They argued that gay and straight, unmarried Floridians risked losing domestic partner benefits, such as health insurance, hospital visitation rights and the ability to make end-of-life decisions.

But proponents say that won't happen because the language in Florida's amendment does not prevent companies or governments with domestic partnership registries -- such as Miami-Dade and Broward counties and the city of North Miami -- from giving benefits to anyone.

In Miami Beach, for example, couples from anywhere in the world can visit the city and register as domestic partners. The registry, created in 2004, gives domestic partners many rights, including hospital visitation, participation in healthcare decisions and emergency medical notification when they're in Miami Beach.

Now, the city's legal department is looking into whether the domestic partner registry will be affected by the amendment's passage, said city spokeswoman Nanette Rodriguez.

`VAGUE WORDING'

Critics of the amendment also expressed concern that its wording was ''vague'' and could possibly lead to lawsuits challenging shared health plans.

"Our message was incredibly complex and required attention," said Derek Newton, campaign manager for Florida Red & Blue, the bipartisan organization that ran the SayNo2 campaign to defeat the amendment. "The yes argument was wrong, but easy to understand."

Sandy Allen, who lives in Northeast Miami-Dade with his partner of 5 ½ years, said he was disappointed that the majority of voters supported the amendment.

''I thought we had done enough of a grass-roots campaign,'' said Allen, 51. ``I thought we had a convincing message.''

Allen called the amendment's passage ``a step backward.''

Allen and his partner, Stephen Kuttner, hoped to marry some day -- in Florida.

Those hoping for the amendment's defeat were disappointed by the outcome, but they knew they were up against several challenges.

Among them: a hotly contested presidential election that dominated voters' attention.