California’s leaders shouldn’t put fundamental rights up for a vote. But the Legislature has nonetheless added Proposition 1 to this November’s ballot.

At first glance, Prop. 1 doesn’t look like anything to worry about — if you, like most Californians (including your columnist), support abortion rights. It comes at a time when even Kansas is voting pro-choice. And its 78-word text seems simple — Prop. 1 adds explicit guarantees of the “fundamental right to choose to have an abortion” and the “fundamental right to choose or refuse contraceptives” to the California Constitution

Legislators behind the measure have said that California needs such language to prevent judges from canceling abortion rights here — like the U.S. Supreme Court did in overturning Roe v. Wade.

That may sound like common sense. But in matters of California governance, common sense often doesn’t apply. Prop. 1 unnecessarily and unintentionally puts at risk the rights it’s designed to protect.

The right to choose is well-established in California. The same part of the state constitution that Prop. 1 would amend — Article 1, Section 1 — already protects the right to choose, because it lists privacy among our inalienable rights. More than 40 years of court precedents have reaffirmed abortion rights here. On top of that, state law straightforwardly guarantees abortion and other reproductive rights.

Asking voters to put these settled rights in the constitution is to pose a question that’s already been answered. Prop. 1 comes with no new benefits — Californians have no rights to gain from the measure — but with significant risks, both legal and political.

Legally, a new constitutional amendment provides a target for abortion opponents to challenge in court — and that’s frightening, now that abortion is no longer constitutional protected nationally. The federal judiciary, now dominated by anti-choice conservatives, might seize on such challenges to undermine the right to choose in California.

Prop. 1 also is vulnerable because of what it leaves out: the limits Roe put on abortion after a fetus becomes viable. In June, two legal scholars, Allison Macbeth of the California Constitution Center and Elizabeth Bernal, an editor of the Hastings Law Journal, publicly urged the Legislature to incorporate the Roe limit into Prop. 1.

Failure to mention Roe, the scholars wrote, could “untether” Prop. 1 from its previous foundation in privacy protection. Doing so could put both reproductive rights and other rights grounded in privacy, such as marriage, in danger of being reinterpreted by the courts.

“There is a substantial risk that the new California constitutional provision will either be interpreted by courts to have no effect, or that its underpinnings will be erased,” Macbeth and Bernal wrote.

These omissions create political risk as well. Prop. 1’s unqualified language gives opponents the opportunity to argue that the measure would establish a right to abortion on demand, at any stage of pregnancy. And that is not popular — while more than 70% of Californians support Roe v. Wade, most voters don’t support abortion in the second trimester or later.

But lawmakers dismissed calls to add limits to Prop. 1. They are confident that the measure will win. But California’s direct democracy often produces unexpected results. I fear, should Prop. 1’s opponents succeed in framing it as an overreaching demand for unlimited abortion, that the measure could lose. That would be a national political disaster and would raise questions here of whether our state constitution’s privacy protections still covered abortion rights.

Even a narrow victory for Prop. 1 also could be damaging for abortion rights. Anti-choice activists and funders around the country, sensing weakness, would pursue future ballot initiatives and actions to keep California’s pro-choice politicians and political funders on defense.

But the biggest problem with Prop. 1 has nothing to do with any possible outcome. It’s that California allows such measures to go on the ballot in the first place.

Our ballot system permits votes on any subject — which makes the Golden State an outlier. Other countries with direct democracy prohibit votes on human rights. They understand that some freedoms are so fundamental that we shouldn’t let the people vote to take them away.

Joe Mathews writes the Connecting California column for Zócalo Public Square.