Proposition 8 would amend the state Constitution to define marriage as only between a man and a woman, but the measure does not address what would happen to the estimated 16,000 same-sex couples who have tied the knot since gay marriage became legal in California on June 17.
If voters next week approve the initiative to ban gay nuptials, legal analysts on both sides of the measure predict that a period of "legal chaos" will ensue, with the legality of same-sex marriages performed between June and November suddenly in doubt.
Borsum and his partner, who have a 15-year-old son, dissolved their domestic partnership before getting married. "Where does that leave us?" asked Borsum, 48. "It's a mess in a legal way, but it's also a mess in how it makes people feel . . . very uncomfortable . . . and kind of sad."
Because a challenge to existing marriages would raise novel questions, no one is certain how the courts would rule. Two family law scholars interviewed by The Times predicted that the marriages would remain intact, while five constitutional scholars were divided over which side the law favors.
California Atty. Gen. Jerry Brown, the state's top law enforcement officer, has said that Proposition 8 would not be retroactive and that existing marriages would stand. But his view is likely to be challenged.
"There is no clear answer," said Erwin Chemerinsky, dean of UC Irvine Law School. "This is ultimately going to have to be litigated by the courts."
It is uncertain how or when the issue would reach the courts if Proposition 8 passes. The question could be raised in an inheritance or property dispute or even by an employer. But in any case filed in state court, the California Supreme Court, which voted 4 to 3 to give gays the right to marry, would be the final arbiter.
Opponents of Proposition 8 could also challenge the entire initiative in federal court, and the ruling there could be appealed all the way to the U.S. Supreme Court. If the high court found the measure constitutional, the California Supreme Court would still probably determine the fate of existing marriages.
Glen Lavy, senior counsel to the Alliance Defense Fund, which is advising proponents of the measure, complained that "what we are going to have is legal chaos." He faulted the state high court for not suspending implementation of its gay marriage ruling until after the election. "Until it is litigated, every same-sex couple with a marriage license is going to be hanging in limbo," said Lavy, whose group opposes gay marriage. He said the state high court might rule that couples would retain certain benefits of marriage -- such as community property designations for assets acquired during the time the marriage was legal -- but would not receive similar benefits in the future.
Supporters of same-sex marriage have expressed hope that existing marriages would be protected by due process rights or the Contracts Clause of the U.S. Constitution.
But after researching the issue, New York University law professor Kenji Yoshino, who favors same-sex marriage, concluded that the U.S. Constitution would offer few protections to existing gay marriages if Proposition 8 passed.
"My hope going into this was that I would find a smoking gun case that would say those marriages would be protected," Yoshino said. "I kept looking and looking and looking, and when I couldn't find one, I was astonished."
He said the U.S. Supreme Court has repeatedly rejected due-process challenges to retroactive legislation. The Contracts Clause, which prevents states from passing laws that impair contracts, would also offer little protection because the court has ruled that "marriage is not a contract" protected by the clause, he said.
Scholars who believe that the law would uphold existing marriages cite a long tradition of courts making constitutional amendments retroactive only if the authors clearly intended them to be so.
"I would think both under federal and state constitutional principles you can't have a retroactive application that would result in a removal of what had been recognized and protected as a fundamental right," said UC Berkeley family law professor Joan Holloway.
UCLA law professor Grace Blumberg agreed, noting that an analogous situation might be cousin marriages. "California allows first cousins to marry and other states don't," she said. "Can California then change its law retroactively to destroy those marriages?"
An expert on family law, Blumberg believes that the California Supreme Court will protect the marriages on state legal grounds, depriving opponents of an appeal to the U.S. Supreme Court.
In deciding the question, the court might examine whether voters intended to invalidate existing marriages when they supported Proposition 8. The measure says that only marriage between a man and a woman is valid and recognized in California. In the official voter handbook, proponents repeat that wording, but also add that same-sex marriage will be invalid "regardless of when or where performed."
While some scholars view that wording as murky, others see clarity.
Santa Clara University law professor Gerald Uelmen believes the initiative would nullify existing marriages. The high court could apply the measure prospectively and still invalidate marriages because Proposition 8 says they are not valid or recognized.
By voting for Proposition 8, "people should realize they are taking something away from people who believe they were married," he said. "What voters would be saying is, 'We don't recognize your marriage.' "
Steve Westfield, who came to California from Nashville to get married in August, said the prospect of Proposition 8 passing has left him feeling he is "on very unsteady ground."
He also said that if California voters do invalidate his marriage, he will want something in return: the money he spent on his marriage license.
"The least I would expect is that the state of California give me my $89 back."
Dolan and Garrison are Times staff writers.