The much-anticipated trial to determine the constitutionality of California's Proposition 8 is scheduled to begin this morning in the case of Perry v. Schwarzenegger. What's at stake in this case, filed in federal district court in San Francisco on behalf of two gay couples, is not just the right of California voters to reaffirm the definition of marriage as only between a man and a woman, but also whether marriage may be otherwise defined in any state.

The entire premise of this litigation is disquieting -- that traditional marriage is nothing but "the residue of centuries of figurative and literal gay bashing," as David Boies, a lawyer for the plaintiffs, has written. According to the plaintiffs, there is just no rational basis for government to privilege marriage between a man and a woman. Thus, in their minds, Proposition 8, which was supported by more than seven million California voters, could have been adopted only as a result of "animus," as the complaint puts it, toward gays and lesbians.

It's disquieting that the trial is taking place in San Francisco, probably the venue most likely to support gay marriage. More than 75 percent of San Francisco voters opposed Proposition 8. That's quite a home-court advantage for same-sex marriage advocates.

But most disquieting for supporters of traditional marriage is a series of pretrial rulings issued by Judge Vaughn R. Walker that have the effect of putting the sponsors of Proposition 8, and the people who voted for it, on trial.

Judge Walker's decisions have been surprising because they differ from those of other judges who have previously scrutinized marriage laws -- in Iowa, Hawaii, Massachusetts, New Jersey and elsewhere in California, for example. In those instances, the courts have decided legal challenges to state marriage laws based on legislative history, scholarly articles and testimony by social scientists and other experts. They have, in some cases, looked for evidence of legislative intent in the statements published in official voter information pamphlets.

But in this case, Judge Walker has ruled that things like TV advertisements, press releases and campaign workers' statements are also relevant evidence of what the voters intended. The judge went so far as to order the Proposition 8 campaign to disclose private internal communications about messages that were considered for public use but never actually used. He has even ordered the campaign to turn over copies of all internal records and e-mail messages relating to campaign strategy.

Most troubling, Judge Walker has also ruled that the trial will investigate the Proposition 8 sponsors' personal beliefs regarding marriage and sexuality. No doubt, the plaintiffs will aggressively exploit this opportunity to assert that the sponsors exhibited bigotry toward homosexuals, or that religious views motivated the adoption of Proposition 8. They'll argue that prohibiting gay marriage is akin to racial discrimination.

To top it all off, Judge Walker has determined that this case will be the first in the Ninth Circuit to allow cameras in the courtroom, with the proceedings posted on YouTube. This will expose supporters of Proposition 8 who appear in the courtroom to the type of vandalism, harassment and bullying attacks already used by some of those who oppose the proposition.

Thankfully, some of Judge Walker's rulings have been overturned. For example, the Ninth Circuit Court of Appeals blocked the disclosure of internal communications among the core Proposition 8 organizers. But there is no question that virtually every ruling by Judge Walker so far has put advocates of traditional marriage at an increasing disadvantage.

Despite this, during the trial, the supporters of Proposition 8 will work hard to demonstrate that it was rational for voters to conclude that marriage is a unique institution that promotes the interests of child-rearing, and that those interests are broader than the personal special interests of the adults involved. And they'll make the case that voters were very much within their rights, when casting their ballots, to consider their own moral and religious views about marriage -- or any other subject.

It remains to be seen whether traditional marriage, and the rights of the voters who approved Proposition 8, will prevail in Judge Walker's courtroom. Most likely, no matter how the judge rules, the Perry case is destined for appeals and a final decision in the United States Supreme Court. But it is during the present trial that the facts in the case will be determined, and it is there that the two sides should be able to present their cases on a level playing field.

Edwin Meese III, the attorney general of the United States from 1985 to 1988, is Chairman of The Heritage Foundation's Center for Legal and Judicial Studies.