Last month 's decision by the California Supreme Court, discovering a right to same-sex marriage in the state constitution, was greeted with glee by homosexual-rights advocates across the country.

But such jubilation is misplaced, because the decision probably will result in a significant and lasting defeat for same-sex marriage advocates, both in California and beyond.

By removing the issue from the political branches and constitutionalizing the policy question, the court 's decision makes compromise less likely and leaves a state constitutional amendment as the only possible response -- one in which same-sex marriage advocates are not likely to prevail.

The California case did not present the question of whether same-sex couples were entitled to any legal recognition of their relationships.

That question already had been settled by the legislators, who established a domestic-partnership law that provided same-sex couples with virtually all the rights and privileges of marriage, including the ability to make medical decisions, file joint state tax returns, and change surnames.

The question before the court was more modest: Does restriction of the title "marriage " to opposite sex couples violate the state constitution?

To this modest question came an answer of judicial immodesty. Indeed, as works of judicial activism go, the California Supreme Court 's decision is the Mona Lisa.

The 100-plus page opinion begins by stating "our task in this proceeding is not to decide whether we believe, as a matter of policy, that the officially recognized relationship of a same-sex couple should be designated a marriage rather than a domestic partnership, but to determine whether the difference in the official names of the relationships violates the California Constitution. "

Of course, a judge writes this kind of a sentence only as a prologue to penning a policy judgment. And the decision does not disappoint.

Doing what once quaintly was thought to be the work of legislators, the court makes quick work of the task of weighing the relative importance of maintaining a traditional definition of marriage against denying same-sex couples the right to have their relationships accorded the "dignity and equal respect " afforded traditional families.

It finds the justifications for maintaining even the label of marriage for traditional opposite-sex couples wanting.

In so doing, the California Supreme Court disregarded the will of the people of California as expressed by 61 percent of the voters, who in 2000 passed an initiative defining marriage as involving one man and one woman.

Now, it 's true that in constitutional systems of government, the will of the majority is not supreme if it is contrary to the constitution. But here there is not a grand and undefined right of marriage in the constitution.

Rather, the court finds that amorphous right in prior activist rulings concerning substantive due process.

By removing the question from the political process, same-sex marriage advocates now eliminate the possibility for incremental changes or compromises regarding the outcome. Rather, opponents of same-sex marriage must now seek a state constitutional amendment if they are to reclaim the issue from the judges.

Given that such an amendment -- which was drafted and had signatures submitted before this present case was decided -- appears on the verge of qualifying for the November ballot, and sensing the degree of discontent that this decision has engendered with Californians, it 's now far more likely that this state constitutional amendment will pass.

And for this, the California Supreme Court, and those who pushed this end-run around the political process, deserve much of the credit.

By asserting themselves into the political process, judges increasingly are viewed as merely political actors, decreasing their respect as neutral arbiters by the people.

The courts should return to a more modest, constitutionally appropriate role, and leave policy questions to the politically accountable branches and the invention of new rights to the constitutional amendment process.

Robert Alt is deputy director of the Center for Legal and Judicial Studies at the Heritage Foundation; www.heritage.org.