In early June, the state Supreme Court will issue its decision on whether gays have a constitutional right to marry. Although it seems unlikely that this rather conservative court — all but one of the seven justices was appointed by a Republican governor — will find such a right to marriage per se, it’s a good guess that the court will acknowledge that same-sex couples have the civil right to enter into committed relationships sanctioned by the state.

Maybe the court will go further, but it will almost certainly go at least that far.

In his questioning of attorneys during oral arguments in March, Justice Ming Chin may have offered a preview of the legal justification for a split-the-baby decision: “Aren’t the rights and responsibilities of domestic partners and marriage partners substantially the same?”

A separate-but-equal decision wouldn’t satisfy proponents of same-sex marriages, of course, but it would further institutionalize the foundation for domestic-partner relationships: that gays and lesbians cannot be denied the personal fulfillment of family life based upon their sexual orientation.

Come November, it appears that civil-rights advocates will have the opportunity to build upon that foundation in the public arena.

Conservative proponents of a ballot measure to place a ban on same-sex marriages in the state Constitution submitted 1.1 million signatures last week to qualify their initiative for the November ballot.

The language of the measure may sound familiar to voters: “Only marriage between a man and a woman is valid or recognized in California.”

It is the same language of Proposition 22, which voters approved in March 2000. The difference is that Proposition 22 was an initiative statute; the new measure is a constitutional amendment.

Such a constitutional amendment would make it impossible for this or a future state Supreme Court to find a right to same-sex marriage in the state Constitution.

There are early indications that this time the opponents of gay marriage may have pushed too far.

Gov. Arnold Schwarzenegger has a pretty good ear for public sensibilities on social issues. He has twice vetoed bills to legalize same-sex marriage in California, each time citing the opinion of the electorate expressed in Proposition 22.

But when asked this month about the new initiative, Schwarzenegger called it “a waste of time” and promised that he will fight it.

If the governor senses this is a case of overkill, there’s a good chance a great many middle-of-the-road Californians will see it the same way.

In addition, polling suggests that Californians’ views on gay marriage have shifted substantially. Proposition 22 passed 61 percent to 39 percent in March 2000. But in August 2005 a survey by the Public Policy Institute of California found that likely voters were evenly split on the question of gay marriages: 46 percent in favor, 46 percent opposed.

The poll also found a widening partisan divide on the issue. In 2005 as in 2000, seven in 10 Republicans were opposed to gay marriage. But the poll showed that 58 percent of Democrats, who had been evenly split in 2000, supported gay marriage five years later. Among independents, the level of support was even higher, 60 percent.

There is also evidence from Arizona that the tide has shifted on the gay marriage issue, at least in the West. In 2006, voters in Arizona rejected a proposed constitutional amendment that would have prohibited both same-sex marriage and any legal measures to confer marriage-like rights to unmarried couples. The vote was close — 51 percent to 49 percent — but it did mark the first time in 28 attempts that any state had rejected an anti-gay marriage ballot measure.

Gay-rights advocates in California may not appreciate having to fight another ballot initiative this fall, but it could represent the next step forward in their quest for full civil rights.

If the Supreme Court were to rule in June that same-sex couples have constitutional rights to everything short of using the word “marriage” and voters were to reject in November a ballot measure to restate California policy forbidding gay marriage, it could lay the foundation for ultimately legalizing gay marriage.

A public vote against a gay-marriage ban might embolden Schwarzenegger to sign the next same-sex marriage bill that makes it to his desk, or it could set the stage for a future governor to do so.

— Timm Herdt is chief of The Star state bureau. Read his political blog “95 percent accurate*” at http://www.TimmHerdt.com.