Back in the ancient mists of 1998, the Santa Clara County Board of Supervisors sold a nicely wrapped bill of goods to the voters. They supported a proposal that limited each supervisor to three terms in office.

This sounded tough until you realized that the supervisors already had a two-term limit. The new measure gave them another four years. It didn’t limit terms. It expanded them.

I was reminded of that sleight-of-hand last week when I read that University of California president Janet Napolitano will propose an 18 percent limit on out-of- state students attending UC campuses.

On the face of it, this sounds reasonable. For years, California students have complained that they have been denied slots at UC schools in favor of out-of-state students who pay higher tuition. The Napolitano proposal feels like a thoughtful compromise.

When you dig into the details, however, you realize that the UC president’s proposal is as much a ruse as the supervisors’ plan in 1998.

It actually allows the percentage of out-of-state students to increase at the majority of UC campuses — and alters nothing at the biggest and most prestigious universities, like Berkeley and UCLA.

That’s because the 18 percent limit applies only to UC campuses that are currently below that cap — places like Santa Cruz, which has 7.6 percent out-of-state students, or Riverside, which has 3.1 percent.

And Berkeley, where 24.4 percent of students come from outside the state? Or UCLA, which has 22.8 percent? They get to stay at their current level. UC’s stance seems to be that if someone says it’s broken, don’t fix it.

Now, I’ve had some sympathy for Napolitano, the former Homeland Security secretary who was chosen as the head of the UC system because of her political skills.

Even when an audit found that the UC system had squirreled away $175 million at a time when tuition was increasing, I shrugged. After all, Napolitano wasn’t absconding with the money. While it was embarrassing — and she had to apologize — it wasn’t anything I haven’t seen local government managers do.

But admission to UC is something that almost every family with a halfway ambitious kid understands. People pay a healthy sum in taxes to keep the UC system afloat. And they do not understand when their kid is denied a slot for economic reasons.

I don’t know the right percentage of out-of-state students. With the Legislature squeezing higher education, I understand why UC is looking for kids who will pay more money. Other states have even higher percentages.

But let’s speak plainly here: The Napolitano proposal on limiting out-of- state students makes the White House explanations for firing FBI director James Comey look like an exercise in transparency.

Consider UC Merced, which enrolled a little more than 1,800 freshmen two years ago. UC’s figures say that 0.4 percent of Merced’s students are from out of state, roughly 7 or 8 kids.

Under the Napolitano proposal, that number would be allowed to grow to 324 (actually, more, because the campus is expanding.). That’s not limiting the number of out-of-state kids, except in some alternate universe. It’s increasing it.

No wonder the UC Board of Regents is expected to approve Napolitano’s proposal at its meeting Thursday. In politics, nothing is so mysterious and wonderful as something that sounds very different than what it is.